TNT2013 Abstract Book (posters) by Phantoms Foundation

TNT2013 index

Foreword

Committees

Poster awards

Sponsors

Exhibitors

Programme

Posters list

Image credit: Experimental deep-subwavelength imaging of the optical local density of state in a nanostructured photonic membrane. Riccardo Sapienza (Kings College, London, UK)

On behalf of the International, Local and Technical Committees, we take great pleasure in welcoming you to Seville (Spain) for the 14th “Trends in NanoTechnology” International Conference (TNT2013).

TNT2013

Foreword

TNT2013 is being held in large part due to the overwhelming success of earlier TNT Nanotechnology Conferences. This high-level scientific meeting series aims to present a broad range of current research in Nanoscience and Nanotechnology worldwide, as well as initiatives such as EU/ICT/FET, MANA, CIC nanoGUNE Consolider, IBEC, DIPC, etc. TNT events have demonstrated that they are particularly effective in transmitting information and promoting interaction and new contacts among workers in this field. Furthermore, this event offers visitors, exhibitors and sponsors an ideal opportunity to interact with each other. In particular, this year, a Graphene one-day Symposium will be organized within TNT2013 in collaboration with ICN2 (Spain). The Graphene Day will entail a plenary session during the morning and the afternoon session will be divided in track A (Graphene science driven oral contributions) and track B (Graphene driven applications Keynotes & Graphene Flagship dedicated session). One of the main objectives of the Trends in Nanotechnology conference is to provide a platform where young researchers can present their latest work and also interact with high-level scientists. For this purpose, the Organising

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Committee provides every year around 40 travel grants for students. In addition, this year, 7 awards (1400 Euros in total) will be given to young PhD students for their contributions presented at TNT. More than 40 senior scientists are involved in the selection process. Grants and awards are funded by the TNT Organisation in collaboration with private bodies and several governmental/research institutions. TNT is now one of the premier European conferences devoted to nanoscale science and technology. We are indebted to the following Scientific Institutions, Companies and Government Agencies for their financial support: Phantoms Foundation, Donostia International Physics Center (DIPC), Universidad Autónoma de Madrid (UAM), NIMS (Nanomaterials Laboratory) and MANA (International Center for Materials and Nanoarchitectonics), Institute for Bioengineering of Catalonia (IBEC), Institut Català de Nanociencia I Nanotecnologia (ICN2), Materials Physics Center (CFM), FEI, American Elements, European Physical Society (EPS), Thermo Scientific, AtMol Integrated Project (EU/ICT/FET) and Viajes El Corte Inglés. We would also like to thank the following companies and institutions for their participation: Raith, IOP Publishing and Institut Català de Nanociencia I Nanotecnologia (ICN2). In addition, thanks must be given to the staff of all the organising institutions whose hard work has helped planning this conference.

TNT 2013 seville (spain)

TNT2013

Organising Committee

Image credit: STM image of the self-assembled structure obtained by depositing DCNQI molecules with the substrate held at 120 K. Roberto Otero (IMDEA-Nano, Spain)

TNT 2013 seville (spain)

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TNT2013 Committees

Organising Committee

Technical Committee

Jose-Maria Alameda (Universidad de Oviedo, Spain) Masakazu Aono (MANA, NIMS, Japan) Robert Baptist (CEA / DRT / LETI, France) Xavier Cartoixa (UAB, Spain) Antonio Correia (Phantoms Foundation, Spain) – Conference Chairman Gianaurelio Cuniberti (TUD, Germany) Pedro Echenique (DICP / UPV, Spain) Jose Maria Gonzalez Calbet (UCM, Spain) Uzi Landman (Georgia Tech, USA) Jose Manuel Perlado Martin (IFN-ETSII / UPM, Spain) Jose Maria Pitarke (CIC nanoGUNE Consolider, Spain) Ron Reifenberger (Purdue University, USA) Jose Rivas (INL, Portugal) Juan Jose Saenz (UAM, Spain) Josep Samitier (IBEC - Universitat de Barcelona, Spain) Frank Scheffold (University of Fribourg, Switzerland) Didier Tonneau (CNRS-CINaM, France)

Carmen Chacón Tomé (Phantoms Foundation, Spain) Viviana Estêvão (Phantoms Foundation, Spain) Maite Fernández Jiménez (Phantoms Foundation, Spain) Paloma Garcia Escorial (Phantoms Foundation, Spain) Pedro Garcia Mochales (UAM, Spain) Adriana Gil (Nanotec, Spain) Conchi Narros Hernández (Phantoms Foundation, Spain) Joaquin Ramon-Laca (Phantoms Foundation, Spain) Jose-Luis Roldan (Phantoms Foundation, Spain)

International Scientific Committee Masakazu Aono (MANA / NIMS, Japan) Emilio Artacho (CIC nanoGUNE Consolider, Spain) Andreas Berger (CIC nanoGUNE Consolider, Spain) Fernando Briones (IMM / CSIC, Spain) Remi Carminati (Ecole Centrale Paris, France) Jose-Luis Costa Kramer (IMM / CSIC, Spain) Antonio Garcia Martin (IMM / CSIC, Spain) Raquel Gonzalez Arrabal (IFN-ETSII / UPM, Spain) Pierre Legagneux (Thales, France) Annick Loiseau (ONERA - CNRS, France) Stefan Roche (ICN and CIN2, Spain) Josep Samitier (IBEC - Universitat de Barcelona, Spain)

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TNT2013 Poster awards

Funded by

Award

European Physical Society

250 Euros

Phantoms Foundation

Tablet

Phantoms Foundation

Tablet

Phantoms Foundation

Tablet

David Prize

Private donation

300 US Dollars

Keren Prize

Private donation

300 US Dollars

TNT 2013 Organisation

TNT 2013 seville (spain)

Free registration to the 2014 Conference

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TNT2013 Sponsors

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TNT2013 Exhibitors

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Exhibitors

TNT2013

Raith is a leading provider and manufacturer of electron and ion beam lithography systems for nanofabrication. Founded in 1980 and headquartered in Dortmund, Germany, the company offers solutions for researchers and engineers in both academic and industry settings. With approximately 120 employees supporting customers in Europe, the Americas, Asia and the Pacific region, Raith provides a professional support infrastructure that delivers added value to customers. Raith includes high level universities, academic institutions as well as companies from high technology business among its clientele. For more information please visit www.raith.com Effective February 15, 2013 Raith and Vistec Lithography announce that they unite their worldwide activities for electron and ion beam lithography and nanofabrication instruments to form one solution provider. Raith has agreed to acquire Vistec Lithography from private equity firm Golden Gate Capital. Raith GmbH Exhibit Contact: Andreas REMSCHEID Konrad-Adenauer-Allee 8 44263 Dortmund- Germany Phone: +49 (0)231 / 95004 - 0 Fax: +49 (0)231 / 95004 - 460 E-mail: sales@raith.com / remscheid@raith.de Web: www.raith.com

Phantoms Foundation, based in Madrid, is a non-profit organization which focus its activities on Nanoscience & Nanotechnology (N&N), bringing together and coordinating the efforts of Spanish and European universities groups, research institutes and companies through the organization of major scientific and technological networks and events, such as ImagineNano or Graphene. Today, the Phantoms Foundation is a key player in structuring and promoting European excellence and improving collaborations in N&N. It is also essential as a platform for spreading excellence on funded projects and for establishing new networks of collaboration.

IOP Publishing provides publications through which leading-edge scientific research is distributed worldwide. Since launch we have expanded rapidly to become one of the leading international STM publishers. We have a global reach, with offices in Philadelphia, Washington DC, Mexico City, Munich, Moscow, St. Petersburg, Wroclaw, Beijing and Tokyo as well as Bristol and London in the UK Web: http://publishing.iop.org/

The Catalan Institute of Nanoscience and Nanotechnology (ICN2) is a private foundation created on 11 July 2003 with the objective of becoming a world-renowned centre for nanoscience and nanotechnology research. It is part of CERCA, the network of Research Centres launched by the Catalan Government as a cornerstone of its longterm strategy to foster development of a knowledgebased economy. ICN2's research lines focus on the newly discovered physical and chemical properties that arise from the fascinating behaviour of matter at the nanoscale. Much of our work is devoted to studying and understanding fundamental physical phenomena associated to state variables as regards electrons, phonons, photons, plasmons, etc.; investigating new properties derived from tailored nanostructures; and establishing new processes for the conception and fabrication of new nanodevices. This work enables functionalisation of nanoparticles, encapsulation of active agents and creation of new nanodevices and nanosensors, through frontier science that has direct implications for various sectors (health, food, energy, the environment, etc.). Campus de la UAB, Edifici ICN2 08193 Bellaterra, Spain E-mail: info@icn2.cat Web: www.icn.cat

Web: www.phantomsnet.net

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TNT2013 Programme Monday – September 09, 2013 08:00-09:15

REGISTRATION

09:15-09:30

TNT2013 Opening Ceremony - Welcome and Introduction

09:30-10:00

Pedro Miguel Echenique (DIPC, Spain) "Electron dynamics at surfaces, nanostructures, graphene and topological insulators”

10:00-10:30

Uzi Landman (Georgia Tech, USA) "Small is different: self-assembly and self-selection of size, shape and form in the nanoscale"

10:30-11:00 11:00-11:30

Danny Porath (The Hebrew University of Jerusalem, Israel) Josep Samitier (IBEC / UB, Spain) "Gradient and uneven nano-patterns distributions for cell adhesion and differentiation studies"

12:00-12:30

Philip Collins (University of California, Irvine, USA) "Single Molecule Bioelectronics"

12:45-13:00

Zi Gu (University of Queensland, Australia) "Layered Double Hydroxide Nanoparticle-based Anti-restenotic Drug Delivery System"

13:00-13:30

15:45-16:00

Xiao Hu (MANA/NIMS, Japan) Enrique Burzuri (Delft University of Technology, The Netherlands) "Measuring magnetic anisotropy in a single-molecule spin transistor"

M. Carmen Miguel (Universidad de Barcelona, Spain) "Dynamics of topological defects in the mechanical deformation of curved nanocrystalline shells"

16:00-16:15

Gema Martinez Criado (ESRF, France) "Probing single nanowires with a hard X-ray nanobeam"

16:15-16:30

Isabel Pastoriza-Santos (University of Vigo, Spain) "Novel Pd based catalyst with high performance for Carbon-Carbon coupling reactions"

16:30-17:00

Tetsufumi Tanamoto (Toshiba Corporation, Japan) "A Reconfigurable Architecture Based on Spin MOSFET"

17:00-17:30

Zhong Lin Wang (Georgia Institute of Technology, USA) "Nanogenerators as new energy technology and piezotronics for functional systems"

17:30-18:00 18:00-18:30

Andreas Leson (Fraunhofer Institute for Material and Beam Technology, Germany) Roberto Otero (UAM / IMDEA Nanoscience, Spain) "Dynamical aspects of molecular self-assembly at solid surfaces"

19:00-19:30

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Coffee Break - Poster Session - Instrument Exhibition

"Reactive Nanometer Multilayers – A Versatile Tool for Cold Joining"

18:30-19:00

Cocktail Lunch (offered by TNT2013) Poster Session - Instrument Exhibition "Antiferromagnetic Topological Insulator: Theory and Material Design"

15:30-15:45

Eduardo Ruiz-Hitzky (ICMM-CSIC, Spain) "Recent developments on functional nanoarchitectures based on clay silicates: from supported graphenes to bionanocomposites"

13:30-15:00 15:00-15:30

David Pozo Perez (BIONAND / CABIMER-University of Seville, Spain) "Engineered nanoparticles for improved neuropeptide biomedical applications immunotargeting and control of autoinmune diseases"

12:30-12:45

Coffee Break - Poster Session - Instrument Exhibition

"Charge Transport in single DNA-Based Molecules"

11:30-12:00

Qiu Cheng Wei (National University of Singapore, Singapore) "Negative Optical Force: Tractor Beam, Light Escalator, and Interface"

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Programme

TNT2013

Tuesday – September 10, 2013 09:00-09:30

Costas Galiotis (FORTH/ICE-HT, Greece) "Mechanical Deformation of graphene and graphene-based nanocomposites"

09:30-10:00

Andrey Turchanin (Universität Bielefeld, Germany) "Molecular engineering of graphene, carbon nanomembranes and their heterostructures for nanotechnology applications"

10:00-10:15

Carlos Sanchez (Empa, Switzerland) "Multitechnique Characterization of Atomically Precise Graphene Nanoribbons"

10:15-10:30

Louis Gaudreau (ICFO-Institute of Photonic Sciences, Spain) "Universal Distance-Scaling of Nonradiative Energy Transfer to Graphene"

10:30-11:00 11:00-11:30

Pierre Seneor (CNRS/Thales, France) Satoshi Moriyama (NIMS/MANA, Japan) Nicolas Agrait (Universidad Autónoma de Madrid, Spain) "Electrical and Mechanical Properties of Atomically Thin Layers of MoS2"

12:30-13:00

Thomas Szkopek (McGill University, Canada) "Observation of the Quantum Hall Effect in Hydrogenated Graphene"

13:00-13:15

Francisco Dominguez-Adame (Universidad Complutense de Madrid, Spain) "Spin-dependent transport in graphene-based nanostructures"

13:15-13:30

O O

"Electron Transport through Field-induced Quantum Dots in Graphene"

12:00-12:30

Coffee Break - Poster Session - Instrument Exhibition "Graphene: new venues for spintronics"

11:30-12:00

Vladimir Falko (Lancaster University, UK) "Electrons in graphene heterostructures with hexagonal crystals"

13:30-15:00

K K K O O

Lunch PARALLEL SESSION (SENIORS) - GRAPHENE TRACK A

15:00-19:00 PARALLEL SESSION (SENIORS) - GRAPHENE TRACK B 20:00

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Guided tour "Reales Alcázares de Sevilla"

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Programme

PARALLEL SESSION (SENIORS) - GRAPHENE TRACK A 15:00-15:30

Pablo Ordejon (ICN2, Spain) "Layered and two-dimensional materials explored from first-principles"

15:30-15:45

Andres Ayuela (Centro de Fisica de Materiales, Spain) "Edge states and flat bands in graphene nanoribbons with arbitrary geometries"

15:45-16:00

Stefano Bellucci (INFN-Laboratori Nazionali di Frascati, Italy) "E.M. Attenuation Performance of Exfoliated Graphite Composites for Microwave Applications"

16:00-16:15

Aron Cummings (ICN2, Spain) "Grain Boundary Resistivity in Polycrystalline Graphene"

16:15-16:30

Cristina Gomez-Navarro (Universidad Autonoma de Madrid, Spain) "Stiffening pristine graphene by controlled defect creation"

16:30-16:45

Choon-Gi Choi (ETRI, Korea)

18:00-18:15

Antonio Javier Martinez Galera (Universität zu Köln, Germany) Tomohiro Matsui (University of Tokyo, Japan) "Intercalation of Kr atoms into Graphene on SiC(0001)"

18:30-18:45

Johannes Mulders (FEI Electron Optics, The Netherlands) "In-situ Raman analysis of possible graphene damage during electron beam or ion beam patterning strategies"

18:45-19:00

O O O

Coffee Break - Poster Session - Instrument Exhibition

"Structural and electronic properties of graphene grown on Cu(111) and on Au(111) surfaces by ethylene irradiation"

18:15-18:30

"Graphene Planar Plasmonic Waveguide Devices"

17:00-18:00

Sergei Lopatin (FEI Co, The Netherlands) "Optimization of imaging conditions for atomic resolution in Titan TEM to minimize radiation damage and to study low angle boundaries in graphene-like materials"

16:45-17:00

Julie Russier (UPR 3572 CNRS - ICT / IBMC, France) "Mask effect: an actor in graphene oxide size dependent modulation of cellular activity and internalization"

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Tuesday – September 10, 2013

Programme

TNT2013

Tuesday â&#x20AC;&#x201C; September 10, 2013 PARALLEL SESSION (SENIORS) - GRAPHENE TRACK B Industrial Session 15:00-15:30

Matthias Schwab (BASF SE, Germany)

"Graphene Technology Platform at BASF"

15:30-16:00

Amaia Zurutuza (Graphenea, Spain)

"Future applications of graphene"

16:00-16:30

Paolo Bondavalli (Thales Research & Technology, France) "Graphene related materials for non-volatile resistive memories: a review"

16:30-17:00

Stefano Borini (Nokia Research Center, UK) "Graphene-enabled innovative solutions for consumer electronics"

17:00-18:00

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Coffee Break - Poster Session - Instrument Exhibition Graphene Flagship Session

18:00-18:15

Mar Garcia Hernandez (ICMM-CSIC, Spain)

"Materials (Graphene Flagship WP1)"

18:15-18:30

Vladimir Falko (Lancaster University, United Kingdom) "Fundamental science of graphene and 2D materials beyond graphene (Graphene Flagship WP3)"

18:30-18:45

Stephan Roche (ICN2, Spain) "Spintronics (Graphene Flagship WP6) "

18:45-19:00

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Discussion and conclusion

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TNT 2013 seville (spain)

09:00-09:30

Philip Moriarty (University of Nottingham, UK) "Mapping Intermolecular Force-fields with Sub-Angstrom Resolution"

09:30-10:00

Leonhard Grill (University of Graz, Austria) "Assembly and manipulation of single functional molecules"

10:00-10:30

Antonio M. Echavarren (ICIQ, Spain)

11:00-13:30

Programme K K

"Synthesis of Nanographene Fragments"

10:30-11:00

Masakazu Aono (MANA / NIMS, Japan)

Coffee Break - Poster Session - Instrument Exhibition

13:30-15:00

Lunch

15:00-19:45

PARALLEL SESSIONS

21:30

Conference Dinner and Poster Award Ceremony

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Wednesday â&#x20AC;&#x201C; September 11, 2013

Programme

TNT2013

Wednesday â&#x20AC;&#x201C; September 11, 2013 PARALLEL SESSION 1 (PHD STUDENTS) 15:00-15:15

Romain Faes (Centre de Recherche Paul Pascal, France) O

Graphene/ Carbon nanotubes "Ultra-Short Carbon Nanotubes as Novel Biotracers"

15:15-15:30

Batrice Vanhorenbeke (IMCN - UCL, Belgium) O

Graphene / Carbon nanotubes "Charge Transfer in Carbon Nanotubes-Supported Nanoparticles"

15:30-15:45

Asieh Kazemi (University of Bath, United Kingdom) O

Graphene / Carbon nanotubes "Stacking-dependent superstructures and taxonomy at armchair interfaces of bilayer/trilayer graphene"

15:45-16:00

Nicolas Leconte (IMCN/NAPS - UCL, Belgium) O

Graphene / Carbon nanotubes "Quantum Hall Effect in Chemically Functionalized Graphene: Oxygen Adsorption Fingerprints"

16:00-16:15

Cristina Mattioli (CEMES-CNRS, France) O

Graphene / Carbon nanotubes "Towards the control in 2D organization of covalent functionalization of graphene surfaces"

16:15-16:30

Vishal Panchal (National Physical Laboratory, United Kingdom) O

Graphene / Carbon nanotubes "Charge transfer and screening behaviour of bilayer graphene devices"

16:30-16:45

Cristina Hermosa (Universidad Autonoma de Madrid, Spain) O

NanoChemistry "Intrinsic electrical conductivity of nanostructured metal-organic polymer chains"

16:45-17:15

Coffee Break - Poster Session - Instrument Exhibition

PARALLEL SESSION 2 (PHD STUDENT) 15:00-15:15

Miguel Anaya (CSIC, Spain) NanoOptics / NanoPhotonics / Plasmonics "Resonant Photocurrent Generation in Dye-Sensitized Periodically Nanostructured Photoconductors by Optical Field Confinement Effects"

15:15-15:30

Paloma A. Huidobro (UAM/IFIMAC, Spain) O

NanoOptics / NanoPhotonics / Plasmonics "Plasmonic Brownian Ratchet"

15:30-15:45

Carl Wadell (Chalmers University of Technology, Sweden) O

NanoOptics / NanoPhotonics / Plasmonics "Absorption engineering in stacked Au-SiO2-Pd nanostructures"

15:45-16:00

Mohammad Danesh (NUS/ECE, Singapore) O

NanoOptics / NanoPhotonics / Plasmonics "Graphene based tunable nano-plasmonic infrared tweezers"

16:00-16:15

Natalia Malashikhina (CICbiomaGUNE, Spain) O

Nanobiotechnologies & Nanomedicine "Development of ultrasensitive bioanalytical assays based on metal and semiconductor nanoparticles"

16:15-16:30

Maria Moffa (Center for Biomolecular Nanotechnologies, IIT@UniLe, Italy) O

Nanobiotechnologies & Nanomedicine "Biomimetic nanofibrous scaffolds for tissue engineering applications"

16:30-16:45

Elena Pinilla-Cienfuegos (ICMOL, Spain) O

Other "Nanopatterning on atomically thin TaS2 conducting layers"

16:45-17:15

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Coffee Break - Poster Session - Instrument Exhibition

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Programme

PARALLEL SESSION 1 (SENIORS) 17:15-17:30

David Alcantara (BIONAND, Spain) O

Nanobiotechnologies & Nanomedicine "Ultrasensitive DNA detection in biological systems using Magnetic fluorochrome nanoparticles"

17:30-17:45

Alan Le Goff (CNRS/Universit de Grenoble, France) O

Nanobiotechnologies & Nanomedicine "Carbon nanotube/enzyme bioelectrodes for implantable glucose/O2 biofuel cells"

17:45-18:00

Lionel Marcon (Interdisciplinary Research Institute, France) O

Nanobiotechnologies & Nanomedicine "Development of Antifouling Polymer-Coated Nanodiamonds for Biological Applications"

18:00-18:15

Ankur Baliyan (Bio-Nano Electronics Research Centre, Toyo University, Japan) Nanostructured and nanoparticle based materials "Synthesis and Characterization of Nano-materials (ultra-thin Fe, FeS nano-sheets and single crystalline Fe nano-cubes) Via Mustard Oil Mediated Solution Phase Process and Their Applications in Sensing"

18:15-18:30

Mohamed Boutinguiza Larosi (University of Vigo, Spain) Nanostructured and nanoparticle based materials

"Production of silver nanoparticles by continuous wave laser in water"

18:30-18:45

Ana B. Descalzo (Universidad Complutense de Madrid, Spain) Nanostructured and nanoparticle based materials "Luminescent Core-Shell Imprinted Nanoparticles Engineered for Targeted FĂśrster Resonance Energy Transfer-Based Sensing"

18:45-19:00

Luis Pinho (Universidad de Cadiz, Spain) Nanostructured and nanoparticle based materials

"TiO2-SiO2 nanocomposite photoactive mesoporous materials for self-cleaning applications"

19:00-19:15

Marketa Zukalova (J. Heyrovsky Institute of Physical Chemistry, Czech Republic) Nanostructured and nanoparticle based materials

"(001)-oriented anatase TiO2 nanosheets as a photoanode material for dye-sensitized solar cell"

19:15-19:30

Silvia Gallego (Instituto de Ciencia de Materiales de Madrid, CSIC, Spain) O

Nanomagnetism and Spintronics "Electronic phase transitions in thin magnetite films"

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Wednesday â&#x20AC;&#x201C; September 11, 2013

Programme

TNT2013

Wednesday – September 11, 2013 PARALLEL SESSION 2 (SENIORS) 17:15-17:30

Ioan Baldea (Universitaet Heidelberg, Germany) O

Theory and modelling at the nanoscale "Transition voltage spectroscopy scrutinized"

17:30-17:45

Katerina Foteinopoulou (ISOM - UPM, Spain) Theory and modelling at the nanoscale "Simulation of the mechanical response of encapsulated individual cells during normal force spectroscopy measurements"

17:45-18:00

Mª Nieves De la Peña (Osalan, Spain) O

Risks-toxicity-regulations "Nanoparticles and occupational risks prevention"

18:00-18:15

Jordi Rull Barrull (CEA/LETI, France) Other "Cleanup: new heterogeneous catalysts based on a new functionallization process of porous material with supercritical CO2"

18:15-18:30

Israel Temprano (University of Cambridge, United Kingdom) O

Other "Surface Science studies of FeS2 for catalytic N2 reduction"

18:30-18:45

Alicia Forment Aliaga (Instituto de Ciencia Molecular, Spain) O

Nanomagnetism and Spintronics "Growth of Self-Assembled Monolayers directly on a ferromagnetic metal surface"

18:45-19:00

Helena Prima Garcia (Molecular Science Institute, Spain) O

Nanomagnetism and Spintronics "Fabrication of robust spin-OLEDs: Towards the control of emitted light with an external magnetic field"

19:00-19:15

Olalla Perez-González (University of the Basque Country - UPV/EHU, Spain) O

NanoOptics / NanoPhotonics / Plasmonics "Optical properties, transport and sensing in metal-molecular aggregate hybrid nanostructures"

19:15-19:30

Witold Jacak (Wroclaw University of Technology, Poland) O

NanoOptics / NanoPhotonics / Plasmonics "Plasmon-polariton propagation in metallic nano-chains for subdiffraction circuits"

19:30-19:45

Violeta Navarro Paredes (Leiden University, The Netherlands) O

NanoChemistry "Following a Fischer-Tropsch catalyst during reaction with STM and SXRD"

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11:00-11:30

Larysa Baraban (Dresden University of Technology, Germany) "Sensing with Schottky barrier based silicon nanowires FET"

11:30-12:00 12:00-12:30

Programme

Speaker to be confirmed

Davide Donadio (MPI for Polymer Research, Germany)

"Heat transport in graphene and three-dimensional nanostructured carbon"

12:30-13:00

Robert Blick (University of Hamburg, Germany) "Nanoelectromechanical Systems for Proteomics"

13:00-13:30

Brigitte Voit (Leibniz-Institut für Polymerforschung Dresden e.V. - IPF, Germany) "Responsive polymersomes and nanocapsules as robust and tunable carrier systems"

13:30-15:00 15:00-15:30

Ricardo Diez Muino (CFM - CSIC-UPV/EHU, Spain) Miguel Angel Gonsalvez (CFM (CSIC-UPV/EHU), Spain) "Evokinetics: A software tool for the analysis of CVD growth of novel 2D materials?"

15:45-16:00

Georg Huhs (Barcelona Supercomputing Center, Spain) "Towards nanoscale DFT calculations with SIESTA and PEXSI"

16:00-16:15

17:00-17:30

Francois Leonard (Sandia National Laboratories, USA) Sebastian Cerdan (Instituto de Investigaciones Biomédicas - CSIC, Spain) "Carbon Nanotubes as Directional probes for Magnetic Resonance Imaging"

18:00-18:15

Alessia Battigelli (CNRS, France) "Dendron-Carbon Nanotubes for Therapeutic Applications"

18:15-18:30

Douglas Galvao (State University of Campinas, Brazil) "On the Formation of Carbon Nanotube Serpentines: A Multi-Million Fully Atomistic Molecular Dynamics Investigation"

18:30-18:45

Jean-Paul Salvetat (CRPP, CBMN, France) "Interfacial electron transfer kinetics at single CCVD multiwalled carbon nanotubes"

18:45-19:00

Jae Eun Jang (DGIST, Korea) "Ultra fast asymmetric MIM diode structure employing vertical MWCNT"

19:00-19:15

Sorin Perisanu (LPMCN, Universit Claude Bernanrd Lyon 1 et CNRS, France) "High Temperature, high current Coulomb Blockade in Single Wall Carbon Nanotubes studied by Field Emission and Mechanical Resonances"

19:15-19:30

K O O O

Coffee Break - Poster Session - Instrument Exhibition

"Broadband Carbon Nanotube Photodetectors with Intrinsic Polarimetry"

17:30-18:00

Ricardo Simoes (Institute for Polymers and Composites IPC/I3N, Portugal) "Modeling the mechanisms for formation of helices and perversions in elastic nanofilaments through molecular dynamics"

16:15-17:00

Coffee Break - Poster Session - Instrument Exhibition

"Nitrogen atoms and molecules landing, reacting, and rebounding at metal surfaces"

15:30-15:45

Laura Rodriguez-Perez (Complutense University of Madrid, Spain) "Towards electroactive carbon nanoforms: chemical modification and propeties"

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Thursday – September 12, 2013

Programme

TNT2013

Friday – September 13, 2013 09:00-09:30

Zeno Gaburro (University of Trento, Italy)

"Flat optics and generalized reflection and refraction laws"

09:30-10:00

Riccardo Sapienza (King's College London, UK) "Nano-optics of complex media"

10:00-10:30

Hernan Miguez (ICMS.US-CSIC, Spain) "Light Absorption and Emission of Nanomaterials in Porous Photonic Structures"

10:30-11:30 11:30-12:00

Ori Cheshnovsky (Tel Aviv University, Israel) Frank Scheffold (University of Fribourg, Switzerland) "Disordered photonic materials derived from three dimensional hyper uniform point patterns"

12:30-12:45

Alasdair Clark (University of Glasgow, United Kingdom) "Creating Molecularly-Reconfigurable Plasmonic Surfaces for Biosensing"

12:45-13:00

Andrea Camposeo (Institute of Nanosciences - CNR, Italy) "Functional polymer nanofibers for photonics, nanoelectronics and biotechnology"

13:00-13:15

Antonio Garcia-Martin (IMM-CNM-CSIC, Spain) "Magneto-optical activity in interacting magnetoplasmonic nanodisks"

13:15-13:30

Sol Carretero Palacios (LMU Munich, Germany) "A microfluidic sensor that maps the velocity field around an oscillating microsphere"

13:30-15:00 15:00-15:30

Gabriel Gomila (IBEC, Spain) Jean-Pierre Aime (CBMN CNRS-Universite Bordeaux, France) "BioInspired Nanotechnology & High Speed AFM Instrumentation"

16:00-16:15

Quirina Ferreira (Instituto de Telecomunicações, Portuga) "Stepwise method to fabricate conductive molecular wires characterized by scanning tunneling microscopy"

16:15-16:45

Genki Yoshikawa (NIMS / MANA, Japan)

18 |

K O O O O

K K O K

"Nanomechanical Membrane-type Surface Stress Sensor"

16:45-17:00

Lunch

"Quantifying the quasi-static dielectric response of nano-objects by imaging electrostatic forces"

15:30-16:00

Coffee Break - Poster Session

"Large anisotropic conductance and band gap fluctuations in nearly-round-shape Bismuth nanoparticles"

12:00-12:30

Closing remarks & TNT2014 announcement

september 09-13, 2013

TNT 2013 seville (spain)

Maria Muñoz, Patricia Ruiz, Valerie Gerard, Yurii Gun`ko, Dmitri N Muraviev

Bastos Arrieta, Julio

Baranov, Denis

Sebastian Pregl, Lotta Römhildt, Larysa Baraban and Gianaurelio Cuniberti

Baek, Eunhye

A. Benchirouf ,S. Vijayaragavan, E. Breyer, D. Lehmann, C. Müller, D. R. Zahn and O. Kanoun

Al-Hamry, Ammar

M. Mohammad

Al Said, Said A Farha

Sehee Lee, Sang, Hee Lee, Yang, Hoon Kim

Ahn, Jiyoung

Gabriela Salomé Yánez-Jácome, Agustina Gómez-Hens

Aguilar-Caballos, Maria de la Paz

Douglas S. Oliveira, Luiz H.G.Tizei, Daniel Ugarte

A. Cotta, Mônica

Spain

Russia

Germany

Saudi Arabia

Korea

Spain

Brazil

NanoChemistry

“Subdiffraction plasmonic chain for magneto-optics enhancement“

NanoOptics / NanoPhotonics / Plasmonics

“Reactive Polymer-Metal Nanocomposites: Dramatic Changes of Surface of Polymer Morphology after Intermatrix Synthesis of Metal Nanoparticles“

“Light-induced Electrical Switching of PorphyrinCovered Silicon Nanowire FETs“

“Comparative Study of Infrared Sensors Based Graphene Oxide and Graphene Oxide/Carbon Nanotube Nanocomposites“

“C-V measurements of a nano device made of PPy-DNA nanowire“

“Screening and Isolation of DNA aptamers against Agrochemicals by using PS-SELEX chip“

“Luminescent determination of fluoroquinolones in milk samples by liquid chromatography/post-column derivatization with terbium oxide nanoparticles”

“Growth mechanisms and kinetic instabilities in Au and Ag-catalyzed InP nanowires“

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

Graphene / Carbon nanotubes

Nanofabrication tools & nanoscale integration

Nanobiotechnologies & Nanomedicine

NanoChemistry

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

student

senior

Only Posters submitted by registered participants and payment processed are listed bellow.

Gabriele Ferrini, Pasqualantonio Pingüe and Luca Gavioli

Cavaliere, Emanuele

R. Torres, R. Escobar, I. Caretti and I. Jiménez

Cascales Fernandez, Jose

Diego Luna, Enrique D. Sancho, Carlos Luna, Gema Cumplido, Felipa M. Bautista, Antonio A. Romero, Alejandro Posadillo, Cristóbal Verdugo, Salvador Rodriguez

Calero, Juan

Ha-Jin Lee and Won san Choi

Byun, Gyo Yeon

Jorge Morgado, Quirina Ferreira

Bragança, Ana

Mark Baxendale, Gavin Mountjoy

Boi, Filippo

M. Ramírez-del-Solar, M. Domínguez, M.C. Barrera-Solano and R. Litrán

Blanco Ollero, Eduardo

M. Valcárcel

Benitez-Martínez, Sandra

A. Al-Hammry, T. Jagemann, C. Müller, S. Schulze, M. Hietschold, O. Kanoun

Benchirouf, Abderrahmane

P. Kuzhir, S. Maksimenko, D. Bychanok, C. Brosseau

Bellucci, Stefano

Sonia Rodriguez-Liviano, Sara Rivera, Yulán Hernández, Jesus M. de la Fuente, Manuel Ocaña

Becerro, Ana Isabel

Italy

Spain

Korea

Portugal

United Kingdom

Spain

Germany

Italy

Spain

Nanostructured and nanoparticle based materials

Graphene / Carbon nanotubes

NanoChemistry

Nanostructured and nanoparticle based materials

Nanobiotechnologies & Nanomedicine

Graphene / Carbon nanotubes

Theory and modelling at the nanoscale

Nanobiotechnologies & Nanomedicine

“Fractal TiO2 nanostructures by non-thermal laser ablation at ambient pressure“

“Controlling the orientation of boron nitride and carbon layers in BN/graphene stackings“

“Biofuel synthesis free of glycerol using CaO as heterogeneous catalysts”

“Evolution of AgX Nanowires into Ag Derivative Nano/microtubes for Highly Efficient Sunlight Photocatalysts“

“Self-assembled monolayers with drug delivery functionality“

“Multiwall Carbon Nanotubes Continuously Filled with Micrometer Length Single Crystals of Ferromagnetic αFe“

“A microwave-hydrothermal synthesis of graphene quantum dots (GQDs) with strongly bluephotoluminescence“

“Total Phenols in Olive Oil Sensor Based on Graphene Quantum Dots“

“Sensitive Strain Sensor Based Chemically Reduced Graphene Oxide and Multi Walled Carbon Nanotubes Hybrid Materials“

“Transport mechanisms and dielectric relaxation of epoxy nanocomposites in dc to microwave range“

“Synthesis and functionalization of biocompatible Tb:CePO4 nanophosphors with spindle-like shape“

senior

student

senior

student

senior

Joseph G. Shapter, Scott McCormick

Dronov, Roman

Radim Hrdy, Marek Bedlek, Vojtech Svatos, Alexander Mozalev, Lukas Kalina, Jaromir Hubalek

Drbohlavova, Jana

Andrade, A.L., Fabris, J.D., Ferreira, J.M.F.

Domingues, Rosana

Paymurzina N.Kh., Latypov K.F., Mukaeva G.R.

Dolomatov, Michail

Dezortsev S.V., Bakhtizin R.Z., Shulyakovskaya D.O., Dolomatova M.M., Kharisov B.R., Eremina S.A.

Dolomatov, Michail

Ricardo Marqués, Lukas Jelinek

Delgado, Vicente

N. Nicoara, J. M. Gómez-Rodríguez

de la Torre, Bruno

F. Rüting, J. Bravo-Abad and F.J. García-Vidal

Cuerda, Javier

Jana Drbohlavova, Petra Businova, Jan Prasek, Jan Pekarek, Radim Hrdy and Jaromir Hubalek

Chomoucka, Jana

V.-M. Freire, A. Ramírez, E. Pascual, J.-L. Andújar and E. Bertran.

Chaitoglou, Stefanos

A. Igartua, G. Barandika, O. Areitioaurtena, G. Mendoza, V. Sáenz de Viteri , A. Marcaide

Cerrillo Redondo, Cristina

Australia

Czech Republic

Brazil

Russia

Spain

Czech Republic

Spain

Nanobiotechnologies & Nanomedicine

Nanostructured and nanoparticle based materials

Nanobiotechnologies & Nanomedicine

Theory and modelling at the nanoscale

Nanostructured and nanoparticle based materials

Theory and modelling at the nanoscale

Graphene / Carbon nanotubes

NanoOptics / NanoPhotonics / Plasmonics

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

Graphene / Carbon nanotubes

Risks-toxicity-regulations

“Effect of Ethanol on Self-assembly of SbpA Surface Layer Protein“

“Fabrication and fluorescence analysis of biofunctionalized gold quantum dots array“

“Synthesis and preparation of magnetic core-shell nano-composites with bioactive glassy material“

“Specific quantum interactions in the molecules and nanoparticles of organic semiconductors“

“Asphaltenes as objects of nanoelectronics“

“New results on Extraordinary Transmission at infrared and optical frequencies“

“Graphene on Pt(111) by Noncontact Atomic Force Microscopy at low temperature“

“Plasmonic lasing in periodic arrays of subwavelength apertures“

“Quenching Effect of Quantum Dots on Bovine Serum Albumin“

“Modified chemical vapor deposition technology to produce graphene with very low pressure pulses of methane“

“Biocompatibility, bactericidal activity and cytotoxicity studies of carbon nanotubes“

senior

student

senior

student

K.V. Vassilevski, E. Escobedo-Cousin, N.G. Wright, A.G. O’Neill, A.B. Horsfall, J.P. Goss, G.H. Wells, M.R.C. Hunt

Hopf, Toby

Pelin Erkoc, A. Sezai Sarac

Güler, Zeliha

F.J.Garcia-Vidal, Esteban Moreno

Gonzalez-Ballestero, Carlos

María Paz Aguilar-Caballos, Agustina GómezHens

Godoy-Navajas, Juan

Repin D. S., Manushkin A. A., Usachev E. Ju

Gelever, Vladimir

S. Peláez and P. A. Serena

García-Mochales, Pedro

Teresa Moskaliovienė

Galdikas, Arvaidas

E. Coronado, S. Kumar, E. Pinilla-Cienfuegos, S. Tatay, L. Català

Forment Aliaga, Alicia

Vanessa Román-Pizarro, Umair Gulzar and Agustina Gómez-Hens

Fernández-Romero, Juan Manuel

Alfredo de la Escosura-Muñiz, Alejandro Chamorro, Carmen de Torres, Arben Merkoçi

Espinoza-Castañeda, Marisol

United Kingdom

Turkey

Spain

Russia

Spain

Lithuania

Spain

Graphene / Carbon nanotubes

Nanobiotechnologies & Nanomedicine

NanoOptics / NanoPhotonics / Plasmonics

NanoChemistry

High spatial resolution spectroscopies under SPM probe

Theory and modelling at the nanoscale

Other

Nanomagnetism and Spintronics

NanoChemistry

Nanobiotechnologies & Nanomedicine

“Effect of etch and growth parameters on the properties of epitaxial graphene grown on 6H-SiC“

“Electrochemical Study of Polypyrrole Coated Electrospun Polycaprolactone Nanofibers and Their Potential Application in Biosensors”

“Non-Markovian effects in waveguide-mediated entanglement between qubits”

“Analytical usefulness of the combined use of Tb4O7 nanoparticles and laccase enzyme for the determination of antioxidants in food samples”

“Hybrid (electronic – x-ray) nanomicroscope (HNОМ– 40) for nanotechnology”

“Size dependence of Young’s modulus of metallic nanowires”

“Stress induced and concentration dependent nitrogen diffusion in austenitic stainless steel“

“Towards a new generation of ultra-dense magnetic memories: Organization, detection and manipulation of magnetic nanoparticles“

Determination of thiol traces in water samples based on the interaction between surfactant, hybrid magnetic core-shell nanospheres loaded with gold nanoparticles, and thiols"

“Prussian blue nanoparticles as novel red-ox specie for sensitive label-free immunosensing using nanochannels: application to parathyroid hormone – related protein (PTHrP) detection“

senior

student

senior

student

Roxana Tomescu, Mihai Kusko

Kusko, Cristian

V. D. Blank, I. A. Perezhogin, Yu. S. Buranova

Kulnitskiy, Boris

Irena Kamińska

Kowalczyk, Dorota

Stefan Brzeziński

Kowalczyk, Dorota

Jana Andzane, Justin D. Holmes, Donats Erts

Kosmaca, Jelena

Vijay Bhooshan Kumar, Aharon Gedanken and Ze’ev Porat

Koltypin, Yuri

Carmen López-López, Olalla Sánchez-Sobrado, José Miguel Luque, Mauricio E. Calvo, Cristina Fernández-López, Ana Sánchez-Iglesias, Luis M. Liz-Marzán and Hernán Míguez

Jiménez-Solano, Alberto

Jenya Tilchin, Georgy I. Maikov, Efrat Lifshitz

Isarov, Maya

A. González-Tudela, L. Martín-Moreno, C. Tejedor, F. J. García-Vidal

Huidobro, Paloma A.

Eva Vrbova, Jana Drbohlavova, Hana Kynclova, Vojtech Svatos, Jaromir Hubalek

Hrdy, Radim

Romania

Russia

Poland

Latvia

Israel

Spain

Israel

Spain

Czech Republic

NanoOptics / NanoPhotonics / Plasmonics

Graphene / Carbon nanotubes

Other

Nanostructured and nanoparticle based materials

Graphene / Carbon nanotubes

NanoChemistry

“Self pulsation behavior of a ring resonator based on nonlinear plasmonic waveguides“

“Crystallography of alfa-, yamma-, and epsilon-iron phases and iron carbides, formed inside carbon nanotubes. HRTEM studies“

“Functionalization of textile materials with bioactive layered silicate“

“Application of a sol-gel method for functionalization of textile materials“

“Transfer and weighing of graphene flakes by using a nanowire mass sensor“

“Formation of gallium micro- and nano-spheres by ultrasonic cavitation and entrapment of organic substances within them“

“Integration of gold nanoparticles in photonic crystals: effect of the interplay between plasmonic and optical cavity resonances“

“Comparison between optical properties of oxidized and non-oxidized MoS2 monolayer“

Low dimensional materials (nanowires, clusters, quantum dots, etc.) NanoOptics / NanoPhotonics / Plasmonics

“Theory of Strong Coupling between Quantum Emitters and Surface Plasmons“

“Preparation and Electrochemical Characterization of Glutathione Modified Gold Nanoelectrodes“

NanoOptics / NanoPhotonics / Plasmonics

NanoChemistry

senior

student

senior

student

senior

Enrique D. Sancho, Diego Luna, Juan Calero, Gema Cumplido, Alejandro Posadillo, Felipa M. Bautista, Antonio A. Romero, Cristóbal Verdugo, Salvador Rodriguez

Luna Durán, Carlos

M. Sieger, M. Valcárcel, B. Mizaikoff

López Lorente, Ángela Inmaculada

S. De Nicola, G. Carotenuto, L. Nicolais, E. Pugliese, M. Ciofini, M. Locatelli, A. Lapucci, R. Meucci

Longo, Angela

Jorge Pérez-Juste, Isabel Pastoriza-Santos

Lobão Nascimento, Ana Cláudia

Ha-Jin Lee, Won San Choi

Lee, Yi Seul

A. Young Kim

Lee, Soo-Keun

Hyelynn Song, Yong Hyup Kim

Lee, Jeong Seok

Md. Shahinul Islam, Won San Choi, Tae Sung Bae, Young Boo Lee

Lee, Ha-Jin

Amaya Romero Izquierdo, Jose Luis Valverde Palomino

Lavin Lopez, Maria del Prado

Monica Simion, Adina Bragaru, Iuliana Mihalache, Razvan Pascu

Kusko, Mihaela

Spain

Italy

Spain

Korea

Spain

Romania

NanoChemistry

Nanostructured and nanoparticle based materials

Graphene / Carbon nanotubes

Nanostructured and nanoparticle based materials

Graphene / Carbon nanotubes

Nanobiotechnologies & Nanomedicine

“Synthesis of a biofuel that integrates glycerin by using heterogeneous supported KF catalysts“

“Attenuated total reflection infrared (ATR-IR) spectroscopy in-situ monitoring of the synthesis of bare gold nanoparticles”

“Thermal expansion of graphite intercalation compounds“

“Synthesis and Catalytic Activity of Gold Nanoparticles Doped Anatase TiO2 Nanoparticles“

“A Novel Approach for Controlling Structure and Size of AgX Nanostructures and Its Application for Visible lightDriven Photocatalyst“

“Synthesis and characterization of monodisperse βcobalt hydroxide using sonochemical method“

“Thermal and electrical interfacial layer of graphene for high performance point emitter“

“Nanonecklace Structure of Carbon Nanotubes for Ultrahigh Loading Metal Nanoparticles“

“Synthesis and characterization of CVD-grown graphene on copper: influence of the synthesis conditions“

“Finding the appropriate substrate for biosensors by monitoring the biomolecular recognition reactions using electrochemical impedance spectroscopy“

student

senior

student

senior

student

senior

T. Steentjes, T. Kudernac, P. Jonkheijm, J. Huskens

Méndez Ardoy, Alejandro

Carlo Morasso, Silvia Picciolini, Renzo Vanna, Marzia Bedoni, Furio Gramatica, Paola Pellacani, Ana Frangolho, Gerardo Marchesini, Andrea Valsesia

Mehn, Dora

Paul A. Martin

Maurel, Agnes

Simon Felix, Jean-Francois Mercier

Maurel, Agnes

A . Forment-Aliaga, S. Tatay , E. Coronado

Mattera, Michele

Kazuki Nakayama, Hiroshi Fukuyama

Matsui, Tomohiro

A.J. Martínez-Galera, J.M. Gómez-Rodríguez

Martín Recio, Ana

Vojtěch Svatošb, Jan Pekáreka, Jana Chomouckaa, Jaromír Hubálek

Márik, Marian

Jan Prasek, Jana Chomoucka, Jana Drbohlavova, Radim Hrdy, Jan Pekarek, Jaromir Hubalek

Majzlikova, Petra

M.Yu. Nazarkin, A. S. Shuliatyev, P. B. Novozhylov, A. N. Belov, D.G. Gromov and I. V. Mel’nikov

Machnev, Andrey

Małgorzata Cieślak, Grzegorz Celichowski

Lyczkowska, Patrycja

Netherlands

Italy

France

Spain

Japan

Spain

Czech Republic

Russia

Poland

Other

Nanobiotechnologies & Nanomedicine

Other

Graphene / Carbon nanotubes

Other

Graphene / Carbon nanotubes

NanoOptics / NanoPhotonics / Plasmonics

Nanostructured and nanoparticle based materials

senior

“Towards Molecular Printboards with Improved Electrical Contact: Tuning the Self-Assembly Capabilities on Gold of β-Cyclodextrin Derivatives Through Chemical Functionalization”

senior

student

senior

student

senior

student

“Surfing plasmonic waves Plasmonic crystal based solid substrate for Surface Enhanced Raman Spectroscopy“

“Transmission and localization length through 1D periodic system with disorder“

“Extraordinary transmission through complex periodic structures“

“Self Assembled Monolayers over Ferromagnetic Surfaces“

“Transport Properties of Graphene Decorated with Oxygen Molecules“

“Scanning Tunneling Microscopy Analysis of Unusual Moiré Patterns on Graphene on Rh(111) Grown under Ultra-High Vacuum Conditions”

“Vertical nanoelectrode system for potential measurement of living cells“

“MWCNTs Based Electrochemical Sensor for Direct Insulin Detection“

“Fiber facet reflection modified with a ZnO nanowire array“

“The synthesis of porous nano-TiO2 films on the basalt fibers“

Yasuhiro Kojima and Hideki Tanaka

Nishida, Naoki

Małgorzata Cieślak

Nejman, Alicja

Julio Bastos-Arrieta, Jordi Bartrolí, Mireia Baeza, Francisco Céspedes, Dmitri N. Muraviev and María Muñoz

Muñoz Martín, Jose

C. Minelli, A.G. Shard

Munz, Martin

Sergey Seriy, and Uriy Kabaldin

Muller, Nina

S. G. Prolongo, M. Sánchez, A. Jiménez-Suárez and A. Ureña

Moriche Tirado, Rocío

Jordi Bartrolí, Mireia Baeza, Francisco Céspedes

Montes Martínez, Raquel

M. Veca, M. Kusko, A. Radoi, E. Vasile

Mihalache, Iuliana

Simon Felix, Agnès Maurel

Mercier, Jean-Francois

A. Garcia-Cristobal

Mengistu, Heruy Taddese

M. Ortiz, M.P. Ariza

Mendez Granado, Juan Pedro

Japan

Poland

Spain

United Kingdom

Russia

Spain

Romania

France

Spain

Nanostructured and nanoparticle based materials

Graphene / Carbon nanotubes

NanoChemistry

Theory and modelling at the nanoscale

Graphene / Carbon nanotubes

Nanostructured and nanoparticle based materials

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

Other

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

Graphene / Carbon nanotubes

“Chiral D-/L-Penicillamine-protected Ag Triangular Nanoplates Synthesized by Substitution Reaction“

“Thermal properties of nanotitania - modified polypropylene fibers“

“Carbon Nanotubes doped with different noble metal nanoparticles by near – percolation amperometric sensors“

“Selective Adhesion Behaviour of Genetically Enginee red Peptides for Chemical Force Microscopy and Nanoparticle Capturing”

"Wavelet and fractal basis instead plane-wave in abinitio calculations"

“Multifunctional GNP-Epoxy Nanocomposites for Structural Health Monitoring“

“Electrochemical Impedance Spectroscopy applied to the optimization of composites based on graphite/epoxy to be used as amperometric sensor“

“Opto-electrical characteristics of PEGylated carbon quantum dots“

“Fano type resonance in Wood anomalies“

“Electronic structure of InN-based nanowires using multiband k  p envelope function method”

“Study of topological defect in graphene“

senior

student

senior

student

senior

student

Juan Manuel Fernández-Romero and Agustina Gómez-Hens

Román-Pizarro, Vanessa

Bartholomeus, Paul

Román-Pérez, Guillermo

A. Blázquez-Castro, A. García-Cabañes, L. Arizmendi, A. Méndez, A. Alcázar, J. C. Stockert, F. Agulló-López, and M. Carrascosa

Ramiro Díaz, José Bruno

Rodríguez Liviano, Sonia

M. Pons

Puente, Antonio

G. Abellán, E. Coronado

Prima Garcia, Helena

Petra Majzlikova, Filip Lechner, Jana Chomoucka, Jana Drbohlavova, Jan Pekarek, Radim Hrdy and Jaromir Hubalek

Prasek, Jan

B. Pérez-López, Carmen C. Mayorga-Martinez, Eden Morales-Narváez, Neus Domingo, Maria Jose Esplandiu, Francesc Alzina, C. M. Sotomayor Torres and A. Merkoçi

Pires, Luis

V. Romeo, G. Carotenuto ,L. Ambrosio, L. Nicolais

Palomba, Mariano

Carlos Sanchez Sanchez, Agustin Rodriguez Gonzalez Elipe, Lety Feria, Javier Fernandez Sanz and Richard M. Lambert

Orozco, Noé

Julio M. Ríos, C. Caro, M.J. Sayagués ,P.J. Merkling, A. P. Zaderenko

Oliva Montero, José María

Spain

Czech Republic

Spain

Italy

Spain

student

“Fluorimetric determination of alkaline phosphatase activity in food using magnetic-gold nanoparticles liposomes hybrids as useful on-flow micro-container devices"

NanoChemistry

senior

“n:: CAD a novel suit for nanotechnology“

Theory and modelling at the nanoscale

senior

student

senior

student

senior

student

“Photovoltaic LiNbO3 particles: Applications to Biomedicine/Biophotonics“

“Giant Magnetoresistance with Temperaturedependent Crossover in FeNi3-graphene Nanocomposites“ “Electron localization in semiconductor nanostructures: from quantum to classical correlations“ “Ionic Liquid Mediated Synthesis and Surface Modification of Multifunctional Mesoporous Eu:GdF3 Nanoparticles for Biomedical Applications“

“Optimization of Spray-Coated MWCNTs Based Working Microelectrodes for Electrochemical sensors“

"Graphene oxide related forms for biosensing applications"

“Carbon nanoscrolls fabrication by a micromechanical technique“

“New directions in organic synthesis: silver-catalyzed Sonogashira cross-coupling of chlorobenzene and phenylacetylene“

“In situ synthesis of short-chain thiols silver nanoparticles (STSNs) for biological purposes: from silver toxicity to tumors treatment. An overview“

Nanobiotechnologies & Nanomedicine

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

Graphene / Carbon nanotubes

NanoChemistry

Nanobiotechnologies & Nanomedicine

Álvaro Caballero, Julián Morales

Vargas Ceballos, Oscar Andrés

Delphine Bouilly, Richard Martel, Sophie Hermans

Vanhorenbeke, Beatrice

O. Súchil, P. Bramon, M. López, J. Agustí and G. Abadal

Torres, Francesc

Andre Neumann, Jesicca Lindlau, Alexander Högele, Georgy I. Maikov, Maya Isarov, Efra Lifshitz

Tilchin, Jenya

N. Gordillo, M. Panizo-Laiz, R. GonzalezArrabal, I. Fernandez-Martinez, J.Y. Pastor

Tejado, Elena

B. Viala, C. Gourgon, F. Duclairoir, J.-H. Tortai

Takacs, Helene

Ha-Jin Lee, Won San Choi

Shin, Hye Jin

J. Maestre, J. Pizarro, S. I. Molina, P. L. Galindo

Scavello, Giovanni

L.A. Trujillo-Cayado, N. Calero, M.C. Alfaro, J. Muñoz

Santos García, Jenifer

E. Castellano-Hernández, G. M. Sacha

Saenz, Juan Jose

M. Darder, P. Aranda, Eduardo Ruiz-Hitzky

Ruiz-Garcia, Cristina

Spain

Belgium

Spain

Israel

Spain

France

Korea

Spain

Other

Graphene / Carbon nanotubes

Other

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

Nanostructured and nanoparticle based materials

Graphene / Carbon nanotubes

NanoChemistry

Theory and modelling at the nanoscale

Graphene / Carbon nanotubes

“Improving the Electrochemical Performance of Graphene Nanosheets as Anode in Half and Full Lithium-Ion Cells“

“Charge Transfer in Carbon Nanotubes-Supported Nanoparticles“

“Multisource Nanoenergy Harvesting and Storage in the Mechanical Domain“

“Impact of excitonic-vibrational coupling in a single colloidal quantum dot emission spectrum“

“Mechanical characterization of nanostructured tungsten films for nuclear applications“

“Magnetic films of metal-graphene-polymer nanocomposites“

“A Facile Approach for Controlled Growth of Metal Oxide Films on Substrates irrespective of Hydrophilic or Hydrophobic Nature“

“Quantitative study of corrugated graphene by tomography and simulation“

“Performance of microfluidics in the preparation of O/W nanoemulsions containing green solvents“

“Simulating the electrostatic interaction of charged thin films by the image charge method and soft computing techniques“

“Green way to clay-supported graphenes“

student

senior

student

senior

student

Jimmy C. Yu

Zhang, Lei

Rosana Zacarias Domingues

Viana Ferreira, Roberta

China

Brazil

Nanobiotechnologies & Nanomedicine

Nanobiotechnologies & Nanomedicine student

student

“Paclitaxel encapsulated magnetoliposomes as drug carrier and magnetic hyperthermia device“ “Redox-Responsive Controlled Gene Transfection Based on Polymer-Conjugated Magnetic Nanoparticles“

Growth mechanisms and kinetic instabilities in Au and Ag-catalyzed InP nanowires 1

Douglas S.Oliveira , Luiz H.G. Tizei , Daniel Ugarte and Mônica A. Cotta 1

Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, Brazil 2 Laboratoire de Physique des Solides, Université Paris-Sud, France monica@ifi.unicamp.br

Abstract: Semiconductor nanowires (NWs) are currently under intense investigation, from the very basic understanding of formation mechanisms of these nanostructures to their possible technological applications. However, these different research lines share a common ground since understanding nanowire synthesis generally leads to new features and applications. As an example, the catalyst material can dramatically change the morphology of the nanowire, but under the right growth conditions it can be used as a parameter for both growth control and modeling. We report here results on the growth of Au and Ag-catalyzed InP nanowires, and discuss the precursor and temperature influence on the growth process in both cases. The microscopy analysis of the ensemble of our nanowires suggests that both vapor-liquid-solid (VLS) and vapor-solid mechanisms are present in our samples, giving rise to different nanowire morphologies and aspect ratios. We have proposed earlier that, for InP nanowire growth under high group III flows, there is a competition between different incorporation pathways of In atoms. This process may lead to a deformation on the triple- phase-line [1], and eventually to mechanical instabilities of the nanoparticle (NP) position on top of the nanowire. Crystallographic phase changes may occur in this case, as well as sidewall wetting by the NP material. Under these conditions, spontaneous diameter oscillations form along InP nanowires grown with Au nanoparticles [2]. The mechanical stability of the nanoparticle on the top of the nanowire depends on the surface energies involved in the problem. Thus changing the metal catalyst from Au to Ag, which has a lower surface energy, should alter the growth equilibrium conditions. Indeed, we observe different contact angles in this case. However, nanowire diameter oscillations are still achievable under different growth conditions than for the Au catalyst, suggesting these are general phenomena which occur under far from equilibrium conditions in VLS growth. References [1] Chiaramonte, T.; Tizei, L. H. G.; Ugarte, D.; Cotta, M. A., Nano Letters 11 (2011), 1934–1940 [2] Oliveira, D. S.; Tizei, L. H. G.; Ugarte, D.; Cotta, M. A., Nano Letters 13 (2013), 9–13

Figures:

Figure 1 – Geometric model for NP mechanical instability due to TPL deformation and sidewall wetting; the associated catalytic radial growth and contact angle variation lead to periodical variations of nanowire diameter and phase changes [2].

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Figure 2 – Scanning electron microscopy images showing morphologies of Ag-catalyzed InP NWs grown under different growth conditions: large apex regions (left) and diameter oscillations (right).

Luminescent determination of fluoroquinolones in milk samples by liquid chromatography/post-column derivatization with terbium oxide nanoparticles Gabriela Salomé Yánez-Jácome, María Paz Aguilar-Caballos, Agustina Gómez-Hens Analytical Chemistry Department. Institute of Fine Chemistry and Nanochemistry. Campus of Rabanales. Annex to Marie Curie Building. University of Córdoba. 14071-Córdoba. Spain.Phone number: +34-957218645, Fax: +34-957218644 e-mail: qa1gohea@uco.es, web: http://www.uco.es/investiga/grupos/FQM-303 The potential usefulness of Tb4O7 nanoparticles (Tb4O7 NPs) for the luminescent detection of fluoroquinolone antibiotic residues in milk samples has been studied by using a liquid chromatography (LC)-post-column derivatization approach. Seven fluoroquinolones of veterinary use were chosen as model analytes to develop this LC method. The derivatization step is based on the post-column reaction between the fluoroquinolones with Tb4O7 NPs to give rise to luminescent chelates, and the measurements are performed at ex 340 and em 545 nm. A modular system has been used to develop this approach (Figure 1).

Figure 1. Modular system used to develop the method: 1, 2 and 3: chromatographic, derivatizing and detection subsystems, A, B and C, MetOH, ACN and acetic acid, DS, delivery system; HPP, high-pressure quaternary gradient pump, HPIV, high-pressure injection valve, LPP, low-pressure pump, L1, mixing reactor, FD, fluorescence detector, PC, personal computer, DR, derivatizing reagent, w1 and w2, waste

The dynamic ranges of the calibration graphs and limits of detection are, respectively: 65 – 900 -1 -1 and 35 ng mL for marbofloxacin, 7.2 – 900 and 2.5 ng mL for ciprofloxacin, 6 - 900 and 2 ng -1 -1 -1 mL for danofloxacin, 50 – 900 and 20 ng mL for enrofloxacin, 35 – 900 and 12 ng mL for -1 -1 sarafloxacin, 5 – 900 and 2 ng mL for oxolinic acid, and 7 – 900 and 2.5 ng mL for flumequine. These features have compared to those provided by previously reported methods 1 using terbium(III) . The precision has been established at two concentration levels of each analyte and expressed as the percentage of the relative standard deviation with values in the range of 1.9-8.1 %. This method has been applied to the analysis of skimmed, semi-skimmed and whole milk samples, with recoveries ranging from 89.0 to 106.5 %. References 1 Rodríguez Díaz, R.C., Fernández Romero, J.M., Aguilar Caballos, M.P., Gómez Hens, A. J. Agric. Food Chem., 54 (2006) 9670-9676.

Screening and Isolation of DNA aptamers against Agrochemicals by using PS-SELEX chip Ji-Young Ahn, Sehee Lee, Sang-Hee Lee, Yang-Hoon Kim Department of Microbiology, Chungbuk National University. 52 Naesudong-Ro, Heungduk-Gu, Cheongju 361-763, South Korea jyahn@chungbuk.ac.kr Abstract

We have described the development of Porous Substrate mediated-Systematic Evolution of Ligands by Exponential Enrichment (referred to as â&#x20AC;&#x153;PS-SELEXâ&#x20AC;?) technique. This method allowed us to screen and isolate high specific aptamers against chemical compounds. Azoxystrobin as a target chemical is a fungicide commonly used in agriculture and has water pollution potential. This is generally used as an active agent protecting plants and fruit/vegetables from fungicidal diseases (1). In PS-SELEX, azoxystrobin was immobilized on sol-gel networks. Especially, sol-gel immobilization is not necessary for linkage/coupling agent (2). Moreover, interacting binding materials can enter into along the complicate internal channels of sol-gels and release to outside. For improving an adhesiveness of solgel microdroplets on the substrate, the porous silicon substrate was newly modified in this study (Figure th 1). The aptamer pools eluted from the 5 selection rounds were cloned and individual clones were sequenced. Identical DNA aptamer pairs were classified and we finally choose the two aptamer species, Azo 5-3 and Azo 5-6 (Table 1), and analysis of the secondary structure of the isolated aptamers was performed with a free energy minimization algorithm using the Mfold program (3). In contrast to traditional chemical SELEX, our strategy provides the following advantages: Simple immobilization of chemical compounds, Easy to handle of aptamers in SELEX process, Decrease the non-specific bind to chip surface. Our data demonstrate that the sol-gel is a convenient partitioning and simplified retrieval method in PS-SELEX process, and isolated aptamer hold great promise for capturing pesticides as a high sensitive biosensing probe.

References [1] Ji-Young Ahn, Analytical Chemistry, 84 (2012) 2647-2653 [2] Ji-Young Ahn, Oligonucleotides, 21 (2011) 93-100 [3] http://frontend.bioinfo.rpi.edu/applications/mfold/cgi-bin/dna-form1.cgi

Figure 1.

PS-SELEX was performed on the small dice of porous silicon substrate. Azoxystrobin contained sol-gels were spotted on the porous chip surface. Considering the 10 to 1 ratio between the number of random ssDNA pools and target chemicals, totally 12 pmole of azoxystrobin were participated in a single round. After stable gelation of sol-gels, 120 pmole of random ssDNA pools were applied to sol-gel integrated chip. Aptamer binders were collected by heat, amplified and regenerated to ssDNA for next round SELEX. (a) assay chamber, (b) sol-gel droplets, (c) SEM image of the PS chip surface, (d) SEM image of sol-gels. Table 1. Sequence of isolated DNA aptamers

C-V measurements of a nano device made of PPy-DNA nanowire 1

Al Said, S. A. Farha , M. Mohammad 1

Department of Physics, Faculty of Science, University of Tabuk, KSA sasaid@ut.edu.sa

The present study reports the fabrication of assembly of DNA-templated polypyrrole (PPy-DNA) nanowire arrays for device characteristic. Photolithographic technique was used to put nano-assembly of Cr/Au inside SiO2 of thickness 200 nm on Si substrate. This arrangement serves as probe contact for C-V measurement. Atomic Force Microscope (AFM) was used to study the surface topography, connection, and uniformity of nanowires interconnects electrodes. The C-V measurements done on the PPY-DNA nanowire show that the nanowire has bistabe molecular states, which is equivalent to logic states 0 and 1 or spin up-down and spin up-up magnetic moments in the magnetic spin orientation. Temperature dependence measurements also show that the capacitance of PPy-Au decreases as the temperature increases while resistivity decreases exponentially as temperature increases from room temperature to 380 K. This study is very useful in the making of low cost nano floating gate, memory FET's, Shchottky diodes ultrafast and ultra-high density memory devices.

Comparative Study of Infrared Sensors Based Graphene Oxide and Graphene Oxide/Carbon Nanotube Nanocomposites 1

A.Al-Hamry , A. Benchirouf , S. Vijayaragavan , E. Breyer , D. Lehmann , C. M체ller , D. R. 2 1 Zahn and O. Kanoun 1

Technische Universit채t Chemnitz, Measurement and Sensor Technology, Chemnitz, Germany 2

Technische Universit채t Chemnitz, Chair of Semiconductor Physics, Chemnitz, Germany Reichenhainer Str. 70, Chemnitz, Germany ammar.al-hamry@etit.tu-chemnitz.de

Abstract Graphene, the two dimensional carbon material, has a high potential for applications in electronic and optoelectronic devices [1]. Owing to its unique band structure, photodetectors with a wide range of wavelengths can be realized [2]. Mono- or multilayered graphene can be produced by several methods, such as chemical vapor deposition (CVD), mechanical exfoliation and sonication of graphite oxide [3]. Graphene oxide is a precursor to produce conductive graphene sheets by reduction; known as reduced graphene .This can be seen as an alternative way to produce large amounts of graphene beside CVD techniques and exfoliation. GO dispersions with about 60% monolayered GO were deposited by spin coating on capton and glass substrates. The obtained films were chemically or thermally reduced to increase their electrical conductivity. In addition, hybrid nanocomposites films of graphene oxide/single wall carbon nanotubes GO/SWNT and graphene oxide/multiwall carbon nanotubes GO/MWNT were fabricated by spin coating. Reduction is carried out as well after the deposition either by heating the substrate to above 200 or by hydroiodic acid HI. The deposited films were characterized by scanning electron microscopy SEM and x-ray photoemission XPS. Images from SEM demonstrate the homogeneity of the CNT/GO solution where CNT is dispersed well in GO that acts as a surfactant as well, as shown in Figure 1. Characterization of the prepared films is also carried out by x-ray photoemission XPS measurements, see Figure 2. The change in carbon and oxygen contents can be monitored by the change of atomic concentrations. This reveals the degree of reduction as well the quality of reduction. The optical sensitivity was measured using a laser diode with a wave length of 980 nm and an optical power of 50 mW in air and at room temperature. The VI characteristics are measured for films based in both composites, i.e. rGO/SWNT and rGO/MWNT. The dark and light currents are shown in Figure 3. The optical response of rGO/SWNT based films shows better light to dark current and hence better sensitivity. Graphene oxide gives optical response comparable to those of pure monolayer exfoliated graphene sheets. Further than that, rGO/CNT nanocomposites showed improved optical response compared with GO only (see Figure 3). Moreover, it seems that rGO/SWNT can have not only thermal but also photoeffect. These properties make GO/SWNT nanocomposites suitable for optical sensors.

References

[1] V. Singh, D. Joung, L. Zhai, S. Das, S.I. Khondaker, S. Seal, Progress in Materials Science 56, 1178 (2011). [2] T. Mueller, F. Xia, P. Avouris, Nat Photon 4, 297 (2010). [3] F. Bonaccorso, Z. Sun, T. Hasan, A.C. Ferrari, Nat Photon 4, 611 (2010).

Figures

Figure 1SEM image for chemically reduced graphene oxide/single wall nanotubes composites rGO/SWNT spin coatd on Si substrate and reduced by HI

Figure 2 XPS spectrum, C1s (left side) and O1s (right side) for thermally, chemically reduced and unreduced GO films

Figure 3 current density measured for rGO/SWNT and rGO/MWNT composites on spin coated films (thickness ~50 nm) irradiated by of infrared laser

Light-induced Electrical Switching of Porphyrin-Covered Silicon Nanowire FETs 1

1,2

Eunhye Baek , Sebastian Pregl , Lotta Römhildt , 1 1,2 Larysa Baraban and Gianaurelio Cuniberti 1

Institute for Materials Science and Max Bergmann Center of Biomaterials, Technische Universität Dresden, Budapester str. 27, 01069 Dresden, Germany 2 Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany eunhye.baek@nano.tu-dresden.de

Abstract

The development and commercialization of novel hybrid intelligent systems with rich functionalities, providing strong benefit in the area of health-care, and electronic applications are among the most crucial topics of the scientific community and industrial players. Nanowires can provide excellent building blocks for hybrid nanoelectronics, due to their efficient charge transport characteristics and good compatibility with molecules [1-3]. Here we present light-induced switching characteristics of porphyrin-coated silicon nanowire field effect transistors (Si NW FETs) and demonstrate their capabilities for design of hybrid nanodevices – consisting of organic complexes and inorganic nanowires. Porphyrin is the organic pigment molecule, absorbing broad range of visible light and release electrons that move easily through molecular bonding [4]. Bottom-up fabricated Si NW based FETs, (see Figure 1) containing nanosized Schottky barriers (SB) [5], are functionalized by porphyrin molecules. Here we show the optoelectrical current-switching depending on porphyrin concentration. Switching current near threshold region of transfer curves, is investigated on time domain (Figure 2). Switching time constant is extracted using exponential growing and decaying function. Also, on/off ratio is characterized according to the concentration change of porphyrin. As the concentration increases, the devices show fast switching due to low resistance of porphyrin. On/off ratio is reduced when the Porphyrin layer is too thick to conduct the light irradiation. Switching of Si NW FETs highly reflects the electrical change of porphyrin molecules by light. To demonstrate significant factors of concentrationdependent switching of porphyrin-covered devices, electrical charging mechanism through molecules and nanowires has been understood, that allows the systematic integration of the molecular hybrid devices.

References [1] Y. Cui and C. M. Lieber, 291, Science (2001) 851-853. [2] Y. Cui, Z. Zhong, D. Wang, W. U. Wang and C. M. Lieber, 3, Nano Lett. (2003) 149-152. [3] Y. Huang, X. Duan, Y. Cui, L. J. Lauhon, K. Kim and C. M. Lieber, 294, Science (2001) 1313-1317. [4] K. M. Kadish, K. M. Smith and R. Guilard, Academic Press (2003) [5] S. Pregl, W. M. Weber, D. Nozaki, J. Kunstmann, L. Baraban, J. Opitz, T. Mikolajick, and G. Cuniberti, Nano Research (2013) DOI: 10.1007/s12274-013-0315-9.

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Figure 1. SEM images of (a) patterning and metal contacts of devices and (b) formation of nickel-silicide in NW to act as Schottky barriers.

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Figure 2. Switching behavior of silicon nanowires based device upon light illumination. Ratio of Id and Id0 of one complete switching period of (a) 50μM, (b) 100μM, and (c) 500μM of porphyrin-covered device.

Subdiffraction plasmonic chain for magneto-optics enhancement D. G. Baranov

1,2,3

1,2

, A. P. Vinogradov , A. A. Lisyansky

Institute for Theoretical and Applied Electromagnetics RAS, 13 Izhorskaya, Moscow 125412, Russia Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny 141701, Moscow Reg., Russia 3 All-Russia Research Institute of Automatics, 22 Sushchevskaya, Moscow 127055, Russia 4 Department of Physics, Queens College of the City University of New York, Flushing, NY 11367, USA baranov.mipt@gmail.com 2

We consider two scenarios of the Faraday rotation enhancement in magneto-optical subdiffraction waveguides. The waveguide itself is a well-known one-dimensional periodic array of plasmonic nanoparticles [1, 2], exhibiting magneto-optical properties [3, 4]. In the first case it is a passive periodic chain of plasmonic nanoparticles embedded into low-loss dielectric MO host medium. It is shown that the propagation of the guided mode travelling along the array is accompanied by rotation of nanoparticles polarization (the Faraday effect). The angle of rotation is dozen times greater than one in the uniform MO material. However, the propagation length of modes of such a chain is strongly inhibited by Ohmic losses. In the second case, we consider gain-assisted 1D chain of composite plasmonic nanoparticles embedded into MO medium. Gain is provided by active molecules in the core of a composite nanoparticle [5, 6]. The guided modes in such an array of composite nanoantennas exhibit high values of the Faraday rotation and propagation length.

[1] M. Quinten et al, Optics Letters 23 (1998) 1331. [2] W. Weber and G. Ford, Physical Review B 70 (2004) pp. [3] B. SepĂşlveda et al, Physical Review Letters 104 (2010) 147401. [4] M. Essone Mezeme et al, Journal of Applied Physics 109 (2011) 014302. [5] S. Wuestner et al, Physical Review Letters 105 (2010) 127401. [ ] P. l str et al, Applied Physics Letters 97 (2010) 073110.

Fig. 1. A schematic drawing of the structure under consideration. Periodic chain of Ag nanoparticles each of radius r is embedded into magneto-optical medium, whose gyrotropy axis is directed along the chain.

Reactive Polymer-Metal Nanocomposites: Dramatic Changes of Surface of Polymer Morphology after Intermatrix Synthesis of Metal Nanoparticles. 1

Julio Bastos-Arrieta , Maria Muñoz , Patricia Ruiz , Valerie Gerard , Yurii Gun`ko Dmitri N 1 Muraviev * 1 Department of Chemistry, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain 2 MATGAS Research Center, Campus de la UAB, 08193, Bellaterra, Barcelona, Spain 3 School of Chemistry, Trinity College Dublin, Dublin 2, Ireland Intermatrix synthesis (IMS) technique coupled with the Donnan Exclusion Effect (DEE) can be successfully applied for the modification of reactive polymers with Functional Metal Nanoparticles (FMNPs). This IMS-DEE version of IMS technique results on the most favourable distribution of FMNPs near the surface of the obtained polymer-metal nanocomposite materials (PMNCMs) (see Fig. 1a). This type of FMNPs distribution in PMNCM is particularly important in their practical applications in such fields as catalysis and electrocatalysis. At the same time modification of the surface of reactive polymers results in dramatic changes of their surface. In this communication we report the results obtained by the modification of reactive polymers such as, ion exchange materials with mono- or bi-metallic Functional Metal NanoParticles (FMNPs) having biocide, catalytic or electrocatalytic properties. The bi-metallic FMNPs consist of a ferromagnetic core coated with a functional metal shell, which provides the final polymermetal nanocomposite with desired functionality. The ferromagnetic nature of the metal core allows the prevention of possible undesirable escape of FMNPs into the medium under treatment by using simple magnetic traps.[1] The modification of polymeric ion exchangers of gel type with FMNPs by using IMS-DEE technique has been shown to result in the appearance of worm-like structure on the surface of the final PMNCM (see Fig.1b). This changes in the morphology of PMNCM leads to the appearance of nanoporosity what enhances their mass-transfer characteristics. The IMS-DEE technique consists of: 1) immobilization (sorption) of metal or metal complex ions (FMNP precursors) onto the functional groups of the polymer, and 2) their chemical or electrochemical reduction. [2, 3]

(a)

(b) Figure 1. SEM images of PMNCM obtained by modification of cationic resin Purolite® C100E with Pd-FMNPs. (a) PMNCM bead cross-section and (b) PMNCM bead surface.

References: [1] A. Alonso et al. Environmentally-safe bimetallic Ag@Co magnetic nanocomposites with antimicrobial activity. Chemical communications 2011, 47(37): 10464-10466. [2 , and D. N. Muraviev: Intermatrix Synthesis of Polymer−Copper Nanocomposites with Tunable Parameters by Using Copper Comproportionation Reaction. Chemistry of Materials 2010, 22(24): 6616-6623. [3] D. N. Muraviev, P. Ruiz, M. Muñoz, and J. Macanás, Novel strategies for preparation and characterization of functional polymer-metal nanocomposites for electrochemical applications. Pure and Applied Chemistry 2008, 80(11): 2425-2437.

Synthesis and functionalization of biocompatible Tb:CePO 4 nanophosphors with spindle-like shape a*

Ana Isabel Becerro, Sonia Rodriguez-Liviano, Sara Rivera, Yulán Hernández, b a Jesus M. de la Fuente, Manuel Ocaña

Instituto de Ciencia de Materiales de Sevilla (CSIC-US), Americo Vespucio 49 Isla de La Cartuja, 41092 Sevilla, Spain b Instituto de Nanociencia de Aragon, Universdidad de Zaragoza. Mariano Esquilor, s/n, 50018 Zaragoza Spain

*anieto@icmse.csic.es Abstract Monoclinic Tb:CePO4 nanophosphors with a spindle-like morphology have been prepared through a very simple procedure, which consists of aging at low temperature (120 ºC) an ethylene glycol solution containing only cerium and terbium acetylacetonates and phosphoric acid, not requiring the addition of surfactants or capping agents (Figure 1). The influence of the heating mode -conventional convection oven (CC) or microwave oven (MW)- and of the Tb doping level on the structural, morphological and luminescent features of the precipitated nanoparticles have been analyzed. This study showed that microwave-assisted heating resulted in an important beneficial effect on the luminescent properties of these nanophosphors (Figure 2). Finally, a procedure for the functionalization of the Tb:CePO4 nanoparticles with aspartic-dextran is also reported. The functionalized nanospindles presented negligible toxicity for Verocells, which along with theirs excellent luminescent properties make them suitable for biomedical applications (Figure 3). References S. Rodríguez-Liviano, F.J. Aparicio, A.I. Becerro, J. García-Sevillano, E. Cantelar, S. Rivera, Y. Hernández, J.M. de la Fuente, M. Ocaña, J. Nano part Res. 15 (2013) 1402.

Figures

Figure 1: TEM images of the CePO4 nanoparticles prepared by aging at 120 ºC for 1 h 0.004 M Ce(acac)3 and 0.15 M H3PO4 solutions in EG using a conventional (a) and microwave oven (b).

Figure 2: Excitation (位em = 542 nm; top) and emission (位ex = 255 nm; bottom) spectra of the Tb0.02Ce0.98PO4 sample obtained by MW heating. The emission spectrum of the Tb0.15Ce0.85PO4 sample synthesized by conventional heating is also included (bottom). (The latter showed the maximum intensity among the Tb doped samples (2-15% Tb) prepared by conventional hating).

Figure 3: Cytotoxicity profiles of the Tb0.02Ce0.98PO4 nanoparticles with VERO cells as determined by MTT assay. Percentage of viability of cells was expressed relative to control cells (n = 5). Results are represented as mean 卤 standard deviations

Transport mechanisms and dielectric relaxation of epoxy nanocomposites in dc to microwave range 1

Stefano Bellucci , P. Kuzhir , S. Maksimenko , D. Bychanok , C. Brosseau 1

INFN-Laboratori Nazionali di Frascati, Via Enrico Fermi 40, 00044 Frascati, Rome, Italy

Research Institute for Nuclear problems of Belarusian State University (INP BSU) Bobruiskaya Str., 11 Minsk 220030 Belarus 3

Université Européenne de Bretagne, Université de Brest, Lab-STICC, CS 93837, 6 avenue Le Gorgeu, 29238 Brest Cedex 3, France bellucci@lnf.infn.it

Abstract We have used several methods to measure the effective complex permittivity of epoxy composites filled with carbonaceous (carbon black (CB), single wall CNT (SWCNT), and multiwalled carbon nanotube (MWCNT) over nine decades of frequency. The composite samples were fabricated by shear mixing. The spectral analysis of permittivity of these nanocomposites is in good agreement with Jonscher’s modelling. We point out, taking these examples, that the experimental frequency dependence of the effective permittivity has a range of interesting properties. Firstly, the likely transport mechanisms responsible for the dielectric relaxation in these samples can be modeled by the dipolar relaxation and anomalous low-frequency dispersion below and above percolation, respectively (Fig. 1).

Figure 1

10 (a)

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'  =0wt.% ''  =0wt.% '  =0.25wt.% ''  =0.25wt.% '  =0wt.% Eq. (1) '' =0wt.% Eq. (1) '  =0.25wt.% Eq. (1) '' =0.25wt.% Eq. (1)

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Figure 1. Effective permittivity spectra of MWCNT-filled diglycidyl ether of bisphenol-A samples at various MWCNT weight fractions below the percolation threshold

Sensitive Strain Sensor Based Chemically Reduced Graphene Oxide and Multi Walled Carbon Nanotubes Hybrid Materials 1

A. Benchirouf , A. Al-Hammry , T. Jagemann , C. Müller , S. Schulze , M. Hietschold , O. Kanoun 1

Technische Universität Chemnitz, Measurement and Sensor Technology, Chemnitz, Germany 2 Technische Universität Chemnitz, Chair of Solid Surfaces Analysis, Chemnitz, Germany Reichenhainer Straße 70, 09126 Chemnitz, Germany Corresponding author: benchirouf@ieee.org

Keywords: reduced graphene oxide, carbon nanotubes, strain sensor, hybrid materials The fast development of flexible electronic in the last decade emphasizes their attractive perspective in numerous applications where flexibility, miniaturization, and functionality are highly recommended. Whereas the essential components in such multifunctional devices are sensors, this requires it to be flexible and robust for integration. This will point on the need of new smart hybrid materials, to ensure these properties. Due to its promising properties i.e. electrical and mechanical, carbon nanotubes (CNTs) are good candidate for the manufacture of strain sensors to improve its performance. But since the pristine CNTs are chemically inactive, surface activation is an essential precondition. Hybrid nanomaterial graphene oxide: multi-walled carbon nanotube (GO:MWCNTs) was synthesize based on the self-assembly of MWCNTs and GO. Compared with pristine MWCNTs, such a nanocomposite could be well dispersed in aqueous solution via the π–π interaction, this will not only allow stabilize the hydrophobic nanotubes, but also provided the MWNTs with a negative charge. Previously, a number of techniques were used to create thin piezoresistive layers on flexible substrate used as graphene-based strain sensor. Bae et. al. used a reactive ion etching and stamping techniques to fabricate strain sensor in a form of rosette on a flexible plastic substrate [1]. In [2] a layer of graphene platelets was achieved by filtration followed by transfer of the resulting layer onto a polymer substrate. Hou et al. used a vacuum filtration of a dispersion of CNT + graphene to form a conductive layer which was afterwards transferred onto a polymethylmethacrylate (PMMA) substrate to form the strain sensor [3]. In this research, we presented a chemically reduced GO (rGO):MWCNT nanocomposites which have high piezoresistivity effects for strain sensors. The conductive thin layer was fabricated and deposited using spin coating on flexible substrate (Kapton HN) to fabricate the strain sensor. After the deposition, the films were chemically reduced to enhance the electrical transport of the composite. The prepared GO:MWCNT films have been characterized using SEM. Results indicate that the MWCNTs were homogeneously dispersed in the GO suspension matrix, as it is shown in Fig. 1. Their piezoresistive properties were investigated under a universal mechanical load test machine, a tensile strain up to 1.7% was used. The strain response of rGO:MWCNT composites showed linearly symmetrical, excellent repeatability, small hysteresis and its strain sensitivity is higher than the MWNT thin films and comparable to the traditional strain sensor. The rGO:MWCNT (5:0.01wt%) nanocomposites show a remarkable positive piezoresistivity of high sensitivity as it is shown in Fig. 2. These results open a new innovative road toward the fabrication of piezoresistive sensors onto flexible substrates with high performance and high linearity.

References [1] S. Bae, Y. Lee, B. Sharma, H. Lee, J. Kim, and J. Ahn, Carbon 51 (2013) 236. [2] S. H. Hwang, H. W. Park, and Y. B. Park, Smart Mater. Struct. 22(1), (2013) 015013. [3] Y. Hou, D. Wang, X. Zhang, H. Zhao, J. Zha, and Z. M. Dang, J. Mater. Chem. C 1, (2013) 515.

Figures

Fig. 1. SEM image of rGO:MWCNT (0.01: 5 wt%) nanocomposite on deposited on Si-wafer

Fig. 2. (a) The variation of normalized resistance (R/R0) (b) The relative change in the resistance of the rGO:MWCNT nanocomposites with content (0.01, 0.05 and 0.1 wt%) of MWCNT and 5 wt% of GO during uniaxial stressing

Total Phenols in Oilive Oil Sensor Based on Graphene Quantum Dots S. Benítez-Martínez, M. Valcárcel Department of Analytical Chemistry, University of Córdoba, Córdoba, Spain. Phone and fax. 957218616. E-mail: qa1meobj@uco.es Abstract Graphene Quantum Dots (GQDs), or Graphene Quantum Disks, is an emerging carbon-based nanomaterial with smaller sheets than 100 nm. GQDs exhibit special properties such as low toxicity, high fluorescent activity, robust chemical inertness and excellent photostability, due to quantum confinement and edge effect. Nowadays, phenolic compounds are receiving considerable attention due to their benefits on health, showing, antioxidant, anti-inflammatory and anti-microbial effects and for their role in prevention of cardiovascular diseases. In this work, GQDs are synthesized by a bottom up method using citric acid as precursor agent [1]. This nanomaterial is used as sensitive sensor for phenols extracted from olive oil. In order to synthesize -1 GQDs, citric acid was heated at 200 ºC for 30 minutes and then dissolved in 10 mg·mL NaOH aqueous solution until homogeneity. Nanoparticles have been characterized by High-Resolution Transmission Electron Microscopy (HR-TEM) and Mid Infrared Spectroscopy (MIR). A liquid-liquid extraction (LLE) was carried out to extract the phenolic fraction from extra virgin olive oil (EVOO)[2]. Adequate volumes of GQDs and phenols (from the extraction) were mixed and measured in a spectrofluorometer. The reaction between GQDs and phenols occurs immediately and the quenching effect is related directly to the total concentration of phenols. The quenching effect can be attributed to the phenols interaction with the GQDs surface-pasivated through carboxylic group, at the edge of GQDs, besides π – π interactions owing to the aromatic structure of both species. GQDs emit blue light (475nm) when they are excited from 365 to 420 nm, the maximum emission being at 379 nm excitation. Nanoparticles synthesized diameters had between 2.8–4.5 nm and flat circular shape, which have been characterized by HR-TEM. MIR spectra show the presence of carboxyl and hydroxyl groups. The influence of pH on the fluorescence emission and on the quenching process has been investigated, finding pH 10.00 more favorable for the phenols interaction in spite of the maximum emission level was found at pH 7.00. Volumes of GQDs and sample were also evaluated. The 1:1 ratio was the most effective value for our study. MeOH has been selected as solvent for the redisolution of the phenolic fraction after the extraction procedure because led to a better FL quenching and shows greater stability over time. Absolute recoveries of spiked Refined Olive Oil (ROO) were better than 73.4 % for gallic acid (simple phenol) and 80.5% for oleuropein (polyphenol), used as model analytes and commonly presents in Spanish olive oil. GQD as sensor has been evaluates in terms of sensitivity, limits -1 of detection (LOD), quantification (LOQ) and precision for both phenols. LOD were 0.21 mg·L for gallic -1 -1 -1 acid and 0.15 mg·L for oleuropein and LOQ were 0.68 mg·L and 0.52 mg·L respectively. Reproducibility of the proposed method has been measured as relative standard deviation (RSD) for five independent measurements of each analyte. RSD was 0.96% for gallic acid and 0.26% for oleuropein. Phenols extraction of real olive oil samples have been carried out. Four different olive oils have been compared: refined, “lampante”, virgin and extra virgin olive oil. Extra virgin olive oil shows more fluorescence quenching than the others types of olive oil due to the higher phenols content. From the best of our knowledge, this is the first time GQDs have been used as sensor of phenols extracted from olive oil, giving rise to a rapid, sensible and selective analytical method. Our studies allow us to state that GQDs are very sensitive to reducing agents such as phenols and polyphenols.

References [1] Y. Dong, J. Shao, C. Chen, H. Li, R. Wang, Y. Chi, Xiaomei Lin, G. Chen. Carbon, 50 (2012), 47384743. [2] F.M. Pirisi, P. Cabras, C.Falqui, M. Migliorini, M. Muggelli. Food Chemistry, 48 (2000),1191-1196.

Figures

Fig.1: Scheme of GQDs FL quenching by interaction of phenols.

A microwave-hydrothermal synthesis of graphene quantum dots (GQDs) with strongly bluephotoluminescence E. Blanco, M. Ramírez-del-Solar, M. Domínguez, M.C. Barrera-Solano and R. Litrán Dep. of Condensed Matter Physics, Campus of Puerto Real, University of Cádiz, Puerto Real (Cádiz), SPAIN eduardo.blanco@uca.es Abstract (Arial 10) Research in photoluminescent nanomaterials is of great interest because of their many applications. It is now widely known that graphene materials can emit light in the visible range, when they are excited at different wavelengths, just in case they are reduced at 3D nanometer scale. In these “zero dimensional” carbon nanodots (C-dots) or graphene quantum dots (GQDs), an energy GAP is induced, its value being dependant on both size and surface traps [1]. Compared with semiconductor QDs, GQDs exhibit nonblinking fluorescence, excellent water solubility, are cheaply produced, are more environmental friendly and could be much safer for biological use [2-4]. Of particular interest and significance is the finding that GQDs can exhibit photoluminescence (PL) emission in the near-infrared (NIR). It should be noted that NIR PL emission of GQDs is particularly significant and useful for in vivo bionanotechnology because of the transparency of body tissues in the NIR region [5]. Samples were prepared from commercial grade, low density ultra-thin graphite (UTG) purchased from Avanzare S.L. (La Rioja, Spain) previously heat-treated at 600ºC under nitrogen flux for two hours. Adequate amount of powder was dispersed in MQ water for a concentration of 1mg/ml assisted by high power ultrasounds for 30 minutes. Dispersions were hydrothermally processed with 4 ml of ammonia in a Teflon reactor placed inside an Ethos 1600 microwave oven at 220ºC for different time intervals reaching a steady pressure of 20 bar. Solutions were filtered with a 0.1 µm membrane and the resulting yellowish solution was kept at 50ºC overnight. Finally, samples were dialysed by a 1000 MWCO membrane. UV-vis absorption spectra of the samples (Fig. 2) show a peak at 215-220 nm (5.8-5.6 eV) that is blueshifted in comparison to that of graphene sheet (270 nm, 4.6 eV). This peak is expected to shift toward higher energies as GQDs size reduces, which is consistent with the quantum confinement effect. –1 Raman spectra present two characteristic vibrations at ≈1350 and ≈1575 cm (Fig. 1), which can be related to the defect band (D band) and the graphite band (G band), respectively [6]. The G band is 2 attributed to the vibration of sp -bonded carbon atoms in a 2D hexagonal lattice, while the D band is associated with vibrations of carbon atoms with dangling bonds in plane terminations of the disordered graphite and is related to the presence of defects and disorder in the nanostructures of carbon materials. The peak frequency of the D band is almost irrespective of nanoparticle size, whilst the G band shows clear size dependence. TEM and AFM measurements show a nanoparticle narrow size distribution with a mean size of 8.4 nm with an average depth of 2 nm (Fig. 4). Photoluminescence (PL) leads to a broad emission peak that is red-shifted when the excitation wavelength changes to higher values with a decreasing of the PL intensity (Fig. 2). This dependence of the emission wavelength and intensity on the excitation energy is a common phenomenon in GQDs. These GQDs exhibit Quantum Yields (QYs) up to 3.5%. The upconverted PL property of the samples was also investigated under excitation wavelengths in the range 700–900 nm (Fig. 4). XPS measurements reveal the presence of functional groups (-O-H, -C-H, -C-O-C and –C=O) located at the surface of the GQDs. These functional groups act as a self-passivation layer on the GQDs surfaces that may facilitate the solubility of GQDs in water as well as the efficient PL properties. Time resolved photoluminescence (TRPL) decays were monitored using a 337nm pulsed laser as excitation source. Each decay curve fits a single-exponential function obtaining a lifetime of 4.2 ns consistent with reported values [7]. In conclusion, these GQDS, prepared by a microwave–hydrothermal method, possess higher QYs and longest lifetime than those previously reported [8], making them very suitable for optoelectronic and biological applications. References [1] H. Li, Z. Kang, Y. Liu, and S.-T. Lee, J Mater Chem, vol. 22, no. 46, (2012) p. 24230. [2] D.R.Larson, W.R.Zipfel, R.M.Williams, S.W.Clark, M.P.Bruchez, F. W. Wise, W. W. Webb, Science, vol. 300, (2003), pp. 1434–1436.

[3] S. T. Yang, X. Wang, H. F. Wang, F. S. Lu, P. J. G. Luo, L. Cao, M. J. Meziani, J. H. Liu, Y. F. Liu, M. Chen, Y. P. Huang, Y. P. Sun, J.Phys. Chem. C , vol. 113, (2009), pp. 18110–18114. [4] S.T.Yang, L.Cao, P.G.J.Luo, F.S.Lu, X.Wang, H.F.Wang, M. J. Meziani, Y. F. Liu, G. Qi, Y. P. Sun, J. Am. Chem. Soc., vol. 131, (2009) pp. 11308–11310 [5] H. Tao, K. Yang, Z. Ma, J. Wan, Y. Zhang, Z. Kang, and Z. Liu, Small, vol. 8, no. 2, (2011), pp. 281– 290. [6] S. Kim, D. Hee Shin, C. Oh Kim, S. Seok Kang, S. Sin Joo, S.-H. Choi, S. Won Hwang, and C. Sone, Appl Phys Lett, vol. 102, no. 5, (2013) p. 053108. [7] L. Bao, Z.-L. Zhang, Z.-Q. Tian, L. Zhang, C. Liu, Y. Lin, B. Qi, and D.-W. Pang, Adv Mater, vol. 23, no. 48, (2011) pp. 5801–5806. [8] Q. Wang, H. Zheng, Y. Long, L. Zhang, M. Gao, and W. Bai, Carbon, vol. 49, no. 9, (2011) pp. 3134–3140. Figures

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Multiwall Carbon Nanotubes Continuously Filled with Micrometer Length Single Crystals of Ferromagnetic -Fe a

Filippo S. Boi , Mark Baxendale , Gavin Mountjoy a

School of Physics and Astronomy, Queen Mary University of London, Mile End Road E1 4NS, London, United Kingdom. b School of Physical Sciences, University of Kent CT2 7NH, Canterbury, United Kingdom. f.boi@qmul.ac.uk

Multiwall carbon nanotubes (MWCNTs) continuously filled with single crystals of the ferromagnetic phase -Fe were produced with a new chemical vapor deposition approach. We report a new perturbed vapor method of synthesis in which the MWCNTs nucleate and form in a flower-like arrangement departing from homogeneously nucleated particles (See Fig.1). These particles are produced by the creation of a local perturbation in a vapor with a high density of Fe and C species obtained from the pyrolysis of a laminar ferrocene/Ar flow. Single-phase filling was achieved by a postsynthesis annealing at 500 ºC for 15 hours in Ar flow. Previously reported synthesis routes use steady-state conditions to guarantee single crystals continuity but result only in small (less than one-micrometre length) single crystals comprising isolated or mixed phases of either -Fe, Fe3C, or -Fe [1-5]. Here, in this new method, a local perturbation was created by a hole in an otherwise flat substrate. This perturbation induces the homogeneous nucleation of nanoparticles when the pyrolysing ferrocene/Ar vapor reaches particular super-saturation conditions. We demonstrate that these conditions can be reached by using high quantities of ferrocene and low vapor flow rates. Once deposited in the substrate, the homogeneously nucleated particles play a fundamental role in the growth of the continuously filled flower-like structures. The large cross-sections of the flower-like structures growing from these particles ensures high capture and delivery feedstock to the base, and the absence of close packing in the emerging MWCNTs ensures a well-defined vapor-capture volume at the tips. Transmission electron microscopy (see Fig. 2) investigations revealed that the continuous single crystals present a diameter much lower than the critical diameter for a single magnetic domain of -Fe (~ 66 nm). The single crystals show mainly a diameter of ~ 30 nm and ~ 55 nm, with uniform single crystals/MWCNTs-walls interfaces and an average length of 19-21 m. DC magnetization measurements at 5 K show that the flower-like structures present a very high saturation magnetization of 189.5 emu/g and a high coercivity of 580 Oe. These ferromagnetic-systems can be ideal candidates for many magnetic applications. For example in magnetic data recording for quantum disk fabrication, as probes for magnetic force microscopy, or for enhancement of the magnetic loss in microwave absorption applications, enhancement of the torque when placed in a constant magnetic field, and oscillatory response on a time-varying magnetic field.

References

[1] Terrones H, López-Urías F, Muñoz-Sandoval E, Rodríguez-Manzo J A, Zamudio A, Elías A L, et al., Solid State Sciences, 8 (2006) 303-20. [2] Dillon F C, Bajpai A, Koos A, Downes S, Aslam Z, Grobert N., Carbon, 50 (2012) 3674-81. [3] Leonhardt A, Ritschel M, Elefant D, Mattern N, Biedermann K, Hampel S, et al., Journal of Applied Physics, 98 (2005) 074315. [4] Gui X, Wei J, Wang K, Wang W, Lv R, Chang J, et al., Materials Research Bulletin, 43 (2008) 34416. [5] Morelos-Gomez A, Lopez-Urıas F, Munoz-Sandoval E, Dennis C L, Shull R D, Terrones H, et al., Journal of Material Chemistry, 20 (2010) 5906-5914.

Figures

Fig.1: Scanning electron micrograph showing the multiwall carbon nanotubes arranged in flower-like structures.

Fig.2: Transmission electron micrograph showing an example of the high morphological quality of the singlecrystals that fill continuously the MWCNTs of the flower-like structures.

Self-assembled monolayers with drug delivery functionality 1

Ana Margarida Bragança, Jorge Morgado

1,2

Quirina Ferreira,

1 Instituto de Telecomunicações, Avenida Rovisco Pais, P-1049-001 Lisboa, Portugal 2 Department of Bioengineering, Instituto Superior Técnico, Avenida Rovisco Pais, P-1049-001 Lisboa, Portugal ana.braganca@ist.utl.pt

Abstract Self-assembly is a versatile technique to prepare materials with multiple and specific functionalities.[1] This is a bottom up process, where individual components are combined, in a process mainly governed by specific interactions, to produce complex systems. The bottom up approach has a huge potential, in terms functional materials fabrication, and is a critical tool in nanotechnology. It has been explored in various areas, namely, in organic electronics,[2] nanomedicine,[3] nanobiotechnology[4], with a particular emphasis on the fabrication of nanostructured materials. In this communication, we report on the use of a layer-by-layer technique to produce self-assembled monolayers with drug delivery function. The complete system combines three different components that are sequentially assembled on a mica substrate. The first one is composed by the poly(allylamine hydrochloride-PAH) polyelectrolyte, a polycation that at neutral pH deposits as flat chains[5]. The second monolayer is made of heparin, a strong polyanion, member of the family of sulfated glycosaminoglycans (GAG), that, due to the electrostatic interaction with the previous monolayer, also deposits as flat chains providing a smooth film. Heparine is the main anticoagulant and a antihrombotic drug[6] and we used it as a scaffold to anchor the drug ( β-blocker ) encapsulated on cyclodextrin (third monolayer). Atomic force microscopy images of monolayers (figure 1 a) and b)) show that the cyclodextrin monolayer has a good affinity towards heparine, since its surface has a very low roughness (root-mean-square (RMS) roughness is approximately 0.230 nm), suggesting that the cyclodextrins are wellorganized/dispersed on heparine-functionalized surface. The drug release from the multilayer surface was monitored by UV-Vis spectroscopy. The film was immersed in an aqueous solution (phosphate-buffered saline solution) at 37ºC and UV-Vis spectra of that solution were recorded over time. Our results revealed that the drug leaves the carrier during the first few hours.

References [1] J. V. Barth, G. Costantini, K. Kern, "Engineering atomic and molecular nanostructures at surfaces", Nature, 437 (2005) , 671-679. [2] Q. Ferreira, L. Alcácer, J. Morgado, “Stepwise Preparation and Characterization of Molecular Wires made of Zinc octaethylporphyrin complexes bridged by 4,4’-bipyridine on HOPG”, Nanotechnology, 22 (2011), 435604. [3] S.K. Sahoo, S. Parveen, J.J. Panda, “The present and future of nanotechnology in human health care”, Nanomedicine: Nanotechnology, Biology, and Medicine, 3 (2007), 4 – 31. [4] L. Xu, Y. Liu, X. Zhang, “Interfacial self assembly of aminoacids and peptides: Scanning Tunneling Microscopy investigation”, Nanoscale, 3 (2011), 4901 – 15. [5] M. R. Kreke, A. S. Badami, J. B. Brady, R. M. Akers, A. S. Goldstein,” Modulation of protein adsorption and cell adhesion by poly(allylamine hydrochloride) heparin films”. Biomaterials, 26 (2005), 2975–81. [6] Sasisekharan R., Raman R., Prabhakar V., “Glycomics Approach to Structure-Function Relationships of Glycosaminoglycans”, Annu. Rev. Biomed. Eng., 8 (2006), 181-231.

Acknowledgements We thank FCT-Portugal, under the projects EXPL/CTM-NAN/0837/2012 and PEst-OE/EEI/LA0008/2013, for financial support. QF thanks FCT for a post-doctoral research grant.

Figures a)

Figure 1 - Topography images (0.66 μm2) of : a) heparine monolayer (RMS≈0.184 nm), b) cyclodextrin monolayer on heparine (RMS≈0.230 nm) obtained by atomic force microscopy on non-contact mode

Evolution of AgX Nanowires into Ag Derivative Nano/microtubes for Highly Efficient Sunlight Photocatalysts 1

Gyo Yeon Byun , Ha-Jin Lee , and Won san Choi

1.*

Department of Chemical and Biological Engineering, Hanbat National University, San 16-1, 2 Dukmyoung dong, Yuseong-gu, Daejeon, 305-719, Republic of Korea, Jeonju Center, Korea Basic Science Institute (KBSI), Dukjin-dong 1ga, Bukjin-gu, Jeonju, Pepublic of Korea E-mail: choiws@hanbat.ac.kr ; Fax: +82 428211692; Te;: +82 428211540 Abstract Sunlight-driven photocatalysts have been an attractive research field due to their high utilization efficiency for solar energy. To effectively use the visible light that comprises 43% of sunlight, efforts have been devoted to designing photocatalysts for high absorption coefficients in the visible and NIR regions. As a result, silver halide (AgX)/Ag nanocomposites have been recently developed and aare considered new visible light photocatalysts. Plasmonic nanoparticles (NPs) are more resistant to 1-3 degradation and exhibit a high absorption coefficient in a broad visible-NIR range. Our study proposes a novel strategy for the synthesis of Ag derivatives (AgX@Ag (X = Cl and Br) or Ag nano/microtubes) using the controlled chemical reduction or electron-beam irradiation of AgX nanowires (NWs), which were formed from the controlled dewetting of a AgX thin film on colloidal particles. The size of the AgX@Ag and Ag nano/microtubes can be controlled using the AgCl NWs as templates and varying the concentration of NaX. By controlling the concentration of NaBr, heterojunction-structured AgCl/AgBr NWs (H-AgCl/AgBr NWs) can be produced from the AgCl NWs due to a partial ion-exchange reaction (low concentration), and the AgBr NWs produced after a complete ion-exchange reaction between Cland Br- were further grown into micrometer-sized AgBr wires (high concentration). The resulting AgX NWs can be transformed into corresponding AgX@Ag or Ag nano/microtubes via a controlled chemical or physical method. The AgX derivatives (AgX@Ag nanotubes (NTs) and AgX NWs) were tested as visible-light-induced photocatalysts for decomposition of methyl orange. The AgX@Ag NTs exhibited the best photocatalytic activities due to the advantages of the core@shell structure, allowing multiple reflections of visible light within the interior cavity, providing a well-defined and clean Ag/AgX interface, and preventing direct adsorption of pollutants on AgX due to the shell structure. These advantages allow AgX@Ag NTs to maintain high catalytic performance even after multiple uses. The approach can also be used as a direct method for preparing Ag nano/microtubes with a tailored size and as a new method for incorporating a AgX NW core into a Ag nano/microtube shell. Our approach is useful for synthesizing various types of one-dimensional heterostructured NWs or metal NTs with controlled structures and properties.

References 1. X. Huang, I. H. El-Sayed, W. Qian, M. A. El-Sayed, J. Am. Chem. Soc. (2006), 128, 2115. 2. Y. Sun, Y. Xia, Analyst (2003), 128, 686. 3. Q. Zhang, J. Ge, T. Pham, J. Goebl, Y. Hu, Z. Lu, Y. Yin, Angew. Chem. Int. Ed. (2009), 48, 3516.

Figure

Figure 1. Schematic depiction of the synthesis of Ag derivatives (AgX@Ag (X = Cl and Br) or Ag nano/microtubes) using the controlled chemical reduction or electron-beam irradiation of AgX nanowires, which are formed from the controlled dewetting of a AgX thin film on colloidal particles. The AgX@Ag nanotubes are used as sunlight-driven photocatalysts.

Biofuel synthesis free of glycerol using CaO as heterogeneous catalysts a

a,c

Juan Calero , Diego Luna ; Enrique D. Sancho ; Carlos Luna ; Gema Cumplido ; Felipa M. Bautista ; a c d b Antonio A. Romero ; Alejandro Posadillo ; Cristóbal Verdugo , ; Salvador Rodriguez . a

Department of Organic Chemistry, University of Cordoba, Campus de Rabanales, Ed. Marie Curie,14014, Córdoba, Spain; b Department of Microbiology, University of Córdoba, Campus de Rabanales, Ed. Marie Curie,14014, Córdoba, Spain; c Seneca Green Catalyst S.L., Campus de Rabanales, 14014, Córdoba, Spain; E-Mail: seneca@uco.es d Crystallographic Studies Laboratory, Andalusian Institute of Earth Sciences, CSIC, Avda. Las Palmeras n°4, 18100, Armilla, Granada, Spain; p72camaj@uco.es Abstract Previous researches allow to obtain a new type of biofuel, applicable to Diesel engines, which integrates the glycerin as monoglyceride (MG), by achieving the partial alcoholisis of triglycerides by application of 1.3 selective lipases [1]. Considering the advantages of this new biofuel compared to the conventional biodiesel, the present study aims to get the same kind of biofuel but using CaO as heterogeneous catalyst, instead of more expensive lipases. In this respect, CaO was recently described as an adequate catalyst for the synthesis of conventional biodiesel [2, 3]. According to these results, when operating with CaO in heterogeneous phase, the quality of biodiesel and glycerol is improved, but, in return, always is obtained a noticeable decrease in catalytic activity, respect to alkaline homogeneous catalysts NaOH or KOH, so that it is required to operate at more elevated temperatures and pressures. In practice, the transformation of vegetable oil to biofuels applicable in conventional diesel engines, consist mainly in reducing its viscosity, since this is the only one parameter of the vegetable oils that differ in more extension respect to fossil diesel. [4]. With this purpose it was performed a ANOVA consisting of 54 experiments, and performed the data analysis with Statgraphics® software. With these data it is obtained the equation which demonstrates that the decrease in viscosity is mainly associated high temperatures as well as the low proportions of methanol respect to sunflower oil used in the methanolisis reaction (Figure 1). The catalyst weight is also an essential parameter for obtaining low viscosity values. Furthermore The variation of viscosity, conversion and selectivity with the temperature fits the Arrhenius equation, as can be seen in Figure 2. The values of kinetic parameters obtained are collected in Table 1. Table1. Activation energy Ea (kcal / mol) and Arrhenius constant, Ln A, obtained according to the data of Figure 2.

In order to assess the possibility of using waste oil [5], under the conditions determined for sunflower oil is also evaluated the influence of the water amount present in the reacion because of the largest drawback of waste oils, that is the high amount of water present (about 3%). Thus, it has been evaluated the water percentage that may be involved in this transesterification reaction without affect the catalytic behaviour of the CaO (figure 3). Results obtained open the possibility to use a cheap solid like CaO as an heterogeneous catalyst to obtain a new biofuel that integrates glycerine with the adventages already described to the biofuel synthesised using more expensive lipases. Acknowlodgements This research was supported by the Spanish Ministry of Economy and Competitiveness (Project ENE 2011-27017), Spanish Ministry of Education and Science (Projects CTQ2010-18126 and CTQ2011-28954-C02-02), FEDER funds and Junta de Andalucía PO8-RMN-03515 and TEP-7723.

References [1] C. Verdugo, D. Luna, A. Posadillo, E.D. Sancho, S. Rodríguez, F. Bautista, R. Luque, J.M. Marinas, A.A. Romero, Catalysis Today, 167 (2011) 107–112. [2] X. Li, H. He, Y. Wang, S. Zhu, X. Piao, Fuel, 87 (2008) 216–221. [3] P-L. Boey, G.P. Maniam, S.A. Hamid, Chem Eng J, 168 (2011) 15–22. [4] G. Knothe, K. Steidley, Fuel Process Technol, 84 (2005) 1059–1065. [5] C.S. Yogesh, S. Bhaskar, K. John, Fuel, 90 (2011) 1309–1324.

Figure 1. The equation of viscosity according to the model set.

Figure 2. Arrhenius plot (Ln r vs. 1 / T) obtained from the evolution with temperature of reaction rate as a parameter related to, conversion (%), selectivity (%) and the inverse value of viscosity (cSt).

Figure3. Variation plot of the viscosity of the transesterification reactions carried out in the optimum conditions, in the presence of increasing amounts of water expressed in percent respect to sunflower oil.

Controlling the orientation of boron nitride and carbon layers in BN/graphene stackings J. Cascales, R. Torres, R. Escobar, I. Caretti and I. JimĂŠnez. Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain jcascales@icmm.csic.es

Abstract Graphene/boron nitride (G/BN) multilayers are very interesting objects because they constitute a repetition of isolated graphene layers, separated by an electrical insulator. Therefore, the outstanding physical properties of graphene can be multiplied by the number of graphene layers in the stacking. The use of boron nitride as the insulating separator is optimal because boron nitride is isoelectronic and isostructural to graphite, hence a single BN layer has a perfect geometrical match to a graphene sheet. Apart from a few studies on G/BN multilayers produced by peeling [1] or transferring [2] followed by the stacking of the two materials, there are no results on the direct growth of these structures. A detailed work on the synthesis of high quality G/BN multilayer structures by vapor deposition techniques is still lacking. We are using ion beam assisted deposition (IBAD) to produce carbon/BN multilayers, with the sequential deposition of carbon by simple evaporation, and boron nitride by boron evaporation simultaneous to nitrogen ion bombardment. Three critical issues which are under study are: (i) the orientation of the formed layers, (ii) their long range order and (iii) the interfacial sharpness. With regards to carbon, its deposition takes place without ion bombardment, and it yields a preferential orientation of the basal planes parallel to the substrate surface. Long range order within the carbon layer can be controlled by the deposition temperature, with increasing perfection at higher temperatures and slower deposition rates. Raman spectroscopy confirms the formation of single or few-layer graphene under certain conditions through the ratio of the 2D to G peaks. With regards to boron nitride, its synthesis requires the participation of nitrogen ions, resulting in a compressive stress in the films that tend to orient the basal planes perpendicular to the growth direction. This is the common growth mode of these materials, as can be observed clearly in the TEM image of Figure 1, corresponding to graphite/BN layers of about 5 nm. However, it is known that the orientation of BN can be controlled through ion bombardment and annealing treatments [3]. For the G/BN multilayers under study here, the BN planes must lie parallel to the growth direction. This is achieved by minimizing the ion energy to reduce the compressive stress, and increasing the growth temperature. A detailed study of the texture of BN films grown with different conditions of ion bombardment and temperature is presented, based on x-ray absorption near edge spectroscopy (XANES) at different angles of incidence, a technique very well suited to study the orientation of Ď&#x20AC;-bonded systems. Finally, the growth of graphene on BN layers with different texture and long range order is examined by Raman spectroscopy.

References [1] S.J. Haigh, A. Gholinia, R. Jalil, S. Romani, L. Britnell, D.C. Elias, K.S. Novoselov, L.A. Ponomarenko, A.K. Geim and R. Gorbachev, Nat.Mater. 9, (2012) 764-767. [2] Z. Liu, L. Song, S. Zhao, J. Huang, L. Ma, J. Zhang, J. Lou and P.M. Ajayan, Nano Lett. 5, (2011) 2032-2037. [3] I. JimĂŠnez, A.F. Jankowski, L.J. Terminello, J.A. Carlisle, D.G.J. Sutherland, G.L. Doll, W.M. Tong, D.K. Shuh, and F.J. Himpsel, Phys.Rev.B 18, (1997) 12025-12037.

Figures

Figure 1. High resolution TEM images from a stack of nanometric carbon and BN layers produced by IBAD, evidencing the reverse texture of the forming layers. Carbon layers have the basal planes parallel to the substrate, whilst BN layers have the basal planes perpendicular to the substrate.

Fractal TiO2 nanostructures by non-thermal laser ablation at ambient pressure Emanuele Cavaliere1, Gabriele Ferrini1, Pasqualantonio Pingue2 and Luca Gavioli1 1 Interdisciplinary Laboratories for Advanced Materials Physics (i-LAMP) & Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, via dei Musei 41, I-25121 Brescia, Italy 2 Laboratorio NEST, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy e.cavaliere@dmf.unicatt.it Abstract Titanium dioxide (TiO2) is one of the most relevant strategic material in many technologically important areas, like heterogeneous catalysis [1-3], photo-assisted oxidation [4], optical [5,6] and photovoltaic devices [7]. To increase the efficiency of these processes through material engineering, routes such as tailoring the absorption edge of the material in the visible light range [8-11], or maximizing the effective surface area are available. A fundamental contribution to the latter may come from realization of fractal materials [12] with nano- and mesoscopic pores, or by hierarchical organization of nanostructures [13,14], enhancing, for instance, the selectivity behavior of catalyst material with high porosity [15]. The synthesis by pulsed laser deposition (PLD) using nanosecond (ns) laser pulses resulted in the formation of nanoparticles (NP) either in low [16], high [17-21,27] or ultra-high vacuum [22], and even in liquid [23], while formation of dendritic-like structures has been reported only for ns-PLD in water [28] or at high argon pressure by employing thousands of ns pulses [24]. Recently, femtosecond (fs) pulsed laser deposition (fs-PLD) has drawn a lot of interest due the process of non-thermal ablation, resulting from the high-energy density and short time-width of the pulse that bring the target surface to a supercritical state [25,26]. It has been shown that laser ﬂuence, sampletarget distance and environment pressure inﬂuence the properties of the deposited material [27-30], but up to now very little is known about TiO2 nanostructure formation at ambient pressure, both for fs and ns regime. In this work we demonstrate that ambient pressure fs-PLD allows to obtain fractal TiO2 nanostructures in crystalline form at room temperature (Figure 1). These structures were studied by scanning electron microscope (SEM), Raman spectroscopy and X-Ray photoemission spectroscopy (XPS). We show that the dendritic aggregations on silicon wafers at room temperature (RT) have a Hausdorff-Besicovich dimension [31] of 1.56, and are hence fractals. The fractals are composed by nanoparticles with an average diameter smaller than 20 nm, with the presence of larger NP with a diameter above 50 nm. We show that the fractal dimension depends on the density of deposited material, while the size distribution of the fractals and NP depends on laser fluence and sample/target distance (Figure 2). XPS shows that the as-deposited nanostructures are TiO2 while Raman spectroscopy reveals that the crystalline structure of fractals and NP is composed by both rutile and anatase phase. Figures

Figure 1. SEM image taken at 10 KeV beam energy. The material was deposited with 150 laser pulses at a 9.6 J/cm2 laser ﬂuence and substratetarget distance of 2 mm. It is possible to distinguish few large nanoparticles with a circular-like shape and aggregates presenting a dendritic shape. The dark background is the silicon wafer substrate. Some of the large NP have been highlighted by dotted circles to evidence the crystalline shape.

Figure 2. Probability of finding a nanostructure with an area A <A0 as a function of laser fluence and sample/target distance. Smaller fractals are found at higher laser fluences, and at 3.5 mm sample/target distance.

References [1] D.W. Flaherty et al. J. Phys. Chem. C 111 (2007) 4765. [2] I.N. Remediakis, N. Lopez, J.K. Norskov, Angew. Chem., Int. Ed. 44 (2005) 1824. [3] A. Kubacka, M. Fernández-García, G. Colón, Chem. Rev. 112 (2012) 1555. [4] C.G. Wu, C.C. Chao, F.T. Kuo, Catalysis Today 97 (2004) 103. [5] H.Y. Zheng, H.X. Qian,W. Zhou, Appl. Surf. Sci. 254 (2008) 2174. [6] A. Pillonnet et al., J. Luminescence 119 (2006) 560. [7] W.X. Que, A. Uddin, X. Hu, J. Power Sources 159 (2006) 353. [8] M. Chiodi, C.P. Cheney, P. Vilmercati, E. Cavaliere, N. Mannella, H.H. Weitering, L. Gavioli, J. Phys. Chem. C 116 (2012) 311 [9] A. N. Mangham et al., J. Phys. Chem. C 115 (2011) 15416 [10] W. J. Yin et al., Phys. Rev. B 82 (2010) 045106 [11] A. Kubacka, M. Fernandez-García, and G. Colon, Chem. Rev. 2012, 112, 1555-1614 [12] F. Gassmann, R. Kotz and A. Wokaun, Europhysics News 34, 176 (2003) [13] Rolison D R 2003 Science 299 1698 [14] F. Di Fonzo et al., Nanotechnology 20 (2009) 015604 [15] S.P. Rigby and L.F. Gladden, J. of Catalysis 180, 44 − 50 (1998) [16] M. Filipescu et al., Appl. Surf. Sci. 253 (2007) 8258 [17] M. Sanz et al., Appl. Phys. A 101, 639 (2010) [18] S. Noel, J. Hermann and T. Itina, Appl. Surf. Sci. 253, 6310 − 6315 (2007) [19] U. Chakravarty et al., J. of Appl. Phys. 108, 053107 (2010) [20] S. Eliezer et al., Phys. Rev. B 69, 144119 (2004) [21] J.C. Alonso et al., App. Surf. Sci 255 (2009) 4933 [22] D. Cattaneo, N. Righetti, C.S. Casari, A. Li Bassi and C.E. Bottani, Appl. Surf. Sci. 253, 7917 (2007) [23] P.V. Kazakevich, A.V. Simakin, V.V. Voronov, G.A. Shafeev, Appl. Surf. Sci. 252 (2006) 4373 [24] P.L. Ong et al., Appl. Surf. Sci. 254, 1909 (2008) [25] P. Lorazo, L. J. Lewis and M. Meunier, Phys. Rev. B 73, 134108 (2006) [26] D. Perez, L.J. Lewis, Phys. Rev. B 67, 184102 (2003) [27] S. Amoruso, G. Ausanio, R. Bruzzese, M. Vitiello, and X. Wang, Phys. Rev. B 71 33406 2005 [28] O. R. Musaev, A. E. Midgley, J. M. Wrobel, J. Yan, M. B. Kruger, J. Appl. Phys. 106, 054306, 2009 [29] H. Köster, K. Mann, Appl. Surf. Sci. 109/110, 428 − 432 (1997) [30] S. Amoruso, R.Bruzzese, X.Wang and J. Xia, Appl. Phys. Lett. 92, 041503 (2008) [31] H. M. Hastings and G. Sugihara, Fractals, Oxford University Press, New York, 1993.

Biocompatibility, bactericidal activity and cytotoxicity studies of carbon nanotubes a

C. Cerrillo , A. Igartua , G. Barandika , O. Areitioaurtena , G. Mendoza , V. Sáenz de Viteri , a A. Marcaide a) IK4-TEKNIKER, Parque Tecnológico de Guipúzcoa, C/ Iñaki Goenaga, 5, 20600 Éibar, Spain. b) Facultad de Farmacia, UPV/EHU, Departamento de Química Inorgánica, Paseo de la Universidad, 7, 01006, Vitoria, Spain. cristina.cerrillo@tekniker.es

Abstract Our research interests are focused on the study of biocompatibility, bactericidal activity and cytotoxicity of biomaterials, coatings and nanoparticles. The studies we are carrying out are aimed to develop new assay procedures that allow predict the impact of these materials on the environment and human health. The ongoing research is directed to make progress in the field of nanotechnology, taking carbon nanotubes (CNTs) as starting point. CNTs are becoming more widely used due to their physical and chemical properties, and their number of applications in a wide range of components and devices (such as composite structural materials, sensors, field emission displays, hydrogen storage materials, tips for scanning probe microscopy and semiconductor devices) is constantly increasing. In the biomedical field, CNTs are being extensively explored for delivery of therapeutic agents, diagnosis of diseases and regenerative materials [1]. This increasing use of CNTs requires more attention to nanotoxicology research, since human exposure to them is inevitable, thus the main objective of this study is to determine the toxicity of CNTs for the environment and human health [2-4]. IK4-TEKNIKER has a huge experience carrying out toxicity of chemical compounds using OECD standard protocols. Our laboratory has recently acquired new equipment to develop in vitro methods for toxicity assessment of nanoparticles, and new test protocols are being implemented to study biocompatibility, bactericidal activity and cytotoxicity of CNTs. The first and one of the most important issues that our study is facing is to find an appropriate method to disperse CNTs in water, the toxicity tests media. Given their hydrophobic nature and tendency to aggregate, CNTs are inadequately soluble or dispersible in most of the common organic and inorganic solvents [5,6]. In this work we start from a previous research carried out in IK4-TEKNIKER, in which two CNTs trademarks have been characterized and tested to identify new solubilization or dispersion methods. The toxicity study includes a series of three in vivo ecotoxicity assays: the inhibitory effect of potentially toxic substances on the light emission of Vibrio fischeri Luminescent bacteria test, Daphnia Magna Acute Immobilization Test and Alga (Selenastrum Capricornutum) Growth Inhibition Test. The Dr. Lange’s LUMIStox test of bioluminescent bacterium is a procedure in which Vibrio Fischeri bacterium produce light as a by-product of its cellular respiration. Toxic substances affect its cellular activity, resulting in a decreased rate of respiration and a corresponding decrease in the rate of luminescence. The test is based on the determination of the influence of chosen toxicant concentrations in the bacterium luminescence after a contact time of 15 minutes. This biotoxicity test measures an inhibitory effect as a function of the dilution of the

sample. So, the EC50-value (Effective Concentration causing 50% inhibition) is the commonly used result parameter. In the Daphnia Magna Test a range of concentrations of the substance investigated exerts different degree of toxic effects on the swimming capability of Daphnia under otherwise identical testing conditions. Certain concentrations result in certain percentages of Daphnia being no longer capable of swimming at 24 and 48 hours, so the immobility percentage at 24-48 hours is determined for each dilution. The measure of inhibitive effect on Daphnia of the test sample is the EC50 value, determined graphically or by calculation. This indicates the concentration of the test sample at which 50% of the Daphnia used become incapable of swimming within the 24-48 hour test period. Finally, the Alga Growth Inhibition Test is based on exponentially-growing cultures of selected green algae (Selenastrum Capricornutum) exposed to various concentrations of the test substance over several generations, under defined conditions during 72 hours. The test is performed in long cell test vials, with algae de-immobilized from algal beads, and optical density is the parameter to determine algal growth inhibition. The result parameter, EC50, is the concentration of test substance which results in a 50% reduction in either growth or growth rate relative to the control.

References [1] Jiyang Fan and Paul K. Chu, Small, 6 (2010) 2080. [2] Xingchen Zhao and Rutao Liu, Environment International, 40 (2012) 244. [3] K. Yang and Z. Liu, Current Drug Metabolism, 13 (2012) 1057. [4] Constantine P. Firme III and Prabhakar R. Bandaru, Nanomedicine: Nanotechnology, Biology, and Medicine, 6 (2010) 245. [5] T. Premkumar, R. Mezzenga, K.E. Geckeler, Small, 8 (2012) 1299. [6] Sang Won Kim, Taehoon Kim, Yern Seung Kim, Hong Soo Choi, Hyeong Jun Lim, Seung Jae Yang and Chong Rae Park, Carbon, 50 (2012) 3.

Figures

Figure 1. a) Vibrio Fischeri, b) Daphnia and c) Algae examples used for toxicity tests.

Acknowledgements The authors would like to acknowledge the ZABALDUZ Program for financing the contract of Cristina Cerrillo with the Basque Country University in collaboration with IK4-TEKNIKER, and the Project NANOREG â&#x20AC;?A common European Approach for the regulatory testing of Nanomaterialsâ&#x20AC;? financed by the European Commission under Contract NMP4-LA-2013-310584.

MODIFIED CHEMICAL VAPOR DEPOSITION TECHNOLOGY TO PRODUCE GRAPHENE WITH VERY-LOW-PRESSURE PULSES OF METHANE V.-M. Freire, S. Chaitoglou, A. Ramírez, E. Pascual, J.-L. Andújar and E. Bertran. Grup FEMAN, Departament de Física Aplicada I Òptica, IN2UB, Universitat de Barcelona, Martí i Franquès 1, 08028, Barcelona, Spain victor.freire@ub.edu Abstract Chemical vapor deposition (CVD) is probably the most popular technology to produce monolayer graphene. However, this technology is associated with relatively high temperatures and supersaturation carbon precursor conditions to produce a graphene monolayer. The goal of this work is to explore a new way of growing graphene on copper over silicon by means of thermally activated chemical vapor deposition using a very low precursor pressure. Growing processes were performed in a reactor with a quartz tube oven at high vacuum conditions. The activated copper substrates were exposed to methane gas at a low pressure and annealed below 1000 ºC. Results indicate a possible solution of Cu on a Ni barrier (grown in order to avoid diffusion of Cu into c-Si) forming a polycrystalline surface Cu/Ni thin layer, which favors the nucleation of graphene. During the annealing Ni/Cu drops were formed and large 4 2 areas of graphene were grown (10 µm , Fig. 1). The characterization by Raman spectroscopy, Energy-dispersive X-Ray spectroscopy (EDS) and Scanning Electron Microscopy (SEM) evidenced that large-areas of the samples appeared 99% coated by graphene. The Raman analysis of these areas assessed the only presence of graphene of one-two layers by showing the characteristic 2D band and the ratio 2D/G ≥ 1 (Fig. 2). Removing Ni/Cu after annealing results in samples of graphene on silicon wafers or on silicon oxide. This facilitates the application of lithographic processes and the possibility to produce graphene-based electronic devices.

References [1] K.S. Novoselov et al., Science, 306 (2004) 666. [2] J. Sun et al., IEEE Transactions on Nanotechnology, 11 (2012) 255 [3] X. Li et al., Science, 324 (2009) 1312 [4] C. A. Howsare et al., Nanotechnology, 23 (2012) 135601 [5] Z. Ni et al., Nano. Res., 1 (2008) 273 [6] V.-M. Freire et al., Jpn. J. Appl. Phys., 52 (2013) 01AK02

Figures

Fig. 1. Raman mapping of areas about 10 Âľm . 99% of the surface is covered with 80% monolayer graphene and 20% of bilayer graphene. 4

Fig. 2. Raman spectra of monolayer and mono-bilayer graphene. Ratio between 2D/G peaks are much bigger than 1 in most of monolayers. Still appeared some defects (D peak) due to the non-crystalline sputtered copper surface.

Quenching Effect of Quantum Dots on Bovine Serum Albumin 1,2

1,2

Jana Chomoucka , Jana Drbohlavova , Petra Businova , Jan Prasek , Jan Pekarek , Radim 1,2 1,2 Hrdy and Jaromir Hubalek 1

where F0 and F are FL intensity of BSA in the absence and presence of QDs, respectively, [Q] is QDs concentration and KSV is the Stern-Volmer quenching constant. The F0/F ratios were calculated and plotted against quencher concentration. After linear fit, KSV were calculated from the slope of the plots [5]. The results show that the quenching constant KSV is variant with different type of QDs and the higher KSV is, the higher is the quenching effect [6]. The FL intensity decreased more significantly in the case of GSH-QDs than in the case of MPA-QDs or TGA-QDs. These results indicated that QDs can effectively quench the FL of BSA in a ligand-dependent manner. Structurally, this is due to the presence of NH2 and COOH groups in the QDs capping agent, namely MPA (1 Ă&#x2014; COOH group); GSH (3 Ă&#x2014; NH2 and 2 Ă&#x2014; COOH groups) and TGA (1 Ă&#x2014; COOH group). Therefore hydrogen bonds can be easily formed between GSH-QDs and BSA. In other words, the number of amino-groups can strongly influence the interactions between BSA and QDs capped with GSH. Therefore, the order of interactions between BSA and QDs is as follows: TGA-QDs < MPA-QDs < GSH-QDs. References [1] Duan, J. L.; Song, L. X.; Zhan, J. H., Nano Research, 2 (2009), 61-68. [2] Chopra, A., et al., Biosensors and Bioelectronics, 44 (2013), 132-135. [3] Liu, P.; Liu, Y. S.; Wang, Q. S., Journal of Chemical Technology and Biotechnology, 87 (2012), 1670-1675. [4] Wang, Q., et al., Journal of Luminescence, 132 (2012), 1695-1700. [5] Ding, L., et al., Journal of Fluorescence, 21 (2011), 17-24.

[6]

Baride, A.; Engebretson, D.; Berry, M. T.; Stanley May, P., Journal of Luminescence, 141 (2013), 99-105.

Figures a

Figure 1. Emission spectra of BSA capped MPA-CdTe QDs (a), GSH-CdTe QDs (b) and TGA-CdTe QDs (c) via covalent interaction at various QDs concentration.

Figure 2. Stern-Volmer plot of BSA FL quenching effect caused by CdTe QDs covalently conjugated with BSA. Acknowledgment This work has been supported by Grant Agency of the Czech Republic under the contract GACR 102/13-20303P, the operational program Research and Development for Innovation, by the project “CEITEC - Central European Institute of Technology” CZ.1.05/1.1.00/02.0068 from European Regional Development Fund and by the project NANOE CZ.1.07/2.3.00/20.0027 from European Social Fund.

Plasmonic lasing in periodic arrays of subwavelength apertures J. Cuerda, F. Rüting, J. Bravo-Abad and F.J. García-Vidal Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain javier.cuerda@uam.es Abstract Creating coherent light sources at the nanoscale has attracted great interest recently. The ability of surface plasmons –collective oscillations of conduction electron in metals— to confine light beyond the diffraction limit makes plasmonic structures ideal candidates for the development of practical nanolasers [1,2,3,4]. In this poster, we discuss our recent theoretical results on the dynamics of optical amplification and lasing action in periodic arrays of subwavelength apertures milled in opaque metallic films. We first introduce an ab-initio computational framework based on a finite-element approach, able to account for the time-dependent nonlinear interplay between the optical response of the gain medium and the plasmonic electromagnetic fields. Then, we apply this theoretical framework to a realistic structure formed by an opaque silver film perforated by a periodic array of slits and clad on each side by an optically pumped dielectric thin film containing Rhodamine dye molecules. Our results show how the enhancement of the local electric field associated with the plasmonic resonances boost significantly the effective gain of the considered system. This enables, not only to achieve full-loss compensation [5], but also obtain self-sustained lasing oscillation. We also present a semiclassical microscopic description of the dynamics underlying the obtained lasing characteristics, together with a comprehensive analysis of the lasing features as a function of the relevant geometrical parameters defining the system. Finally, we discuss the application of our theoretical approach to provide the theoretical foundation of recent experimental results on plasmonic lasing action in metal hole arrays [6].

References [1] M. A. Noginov, G. Zhu, A. M. Belgrave, R. Bakker, V.M. Shalaev, E. E. Narimanov, S. Stout, E. Herz, T. Suteewong, and U. Wiesner “Demonstration of a spaser-based nanolaser”, Nature 460, 1110–1112 (2009). [2] R. F. Oulton, V. J. Sorger, T. Zentgraf, R.-M. Ma, C. Gladden, L. Dai, G. Bartal, and X. Zhang “Plasmon lasers at deep subwavelength scale”, Nature 461, 629–631 (2009). [3] P. Berini and I. de Leon, “Surface plasmon–polariton amplifiers and lasers”, Nature Photonics 6, 16–24 (2012). [4] J. Bravo-Abad and F. J. García-Vidal, “Plasmonic lasers: A sense of direction”, Nature Nanotechnology (News and Views) (2013). [5] R. Marani, A. D’Orazio, V. Petruzzelli, S. G. Rodrigo, L. Martín-Moreno, F. J. García-Vidal, and J. Bravo-Abad, New Journal of Physics 14, 013020 (2012). [6] F. van Beijnum, P. J. van Veldhoven, E. J. Geluk, M. J. A. de Dood, G. W. ’t Hooft, and M. P. van Exter “Surface Plasmon Lasing Observed in Metal Hole Arrays”, Physical Review Letters 110, 206802 (2013).

Figure 1: Subwavelength slit array structure studied.

(a)

(b)

Figure 2: (a) Spatial distribution of Normalized Population Inversion density in a slit array. Red (blue) accounts for the maximum (minimum) of the scale. (b) Transmission spectra for various pump amplitudes. SP-resonance is enhanced (gain amplification regime) or depleted (absorption regime), depending on the value of the pump. (c) Lasing regime is achieved for high enough pump. Lasing action shows up in linear emitted power vs. input pump power. (c)

Graphene on Pt(111) by Noncontact Atomic Force Microscopy at low temperature B. De La Torre1, N. Nicoara2, J. M. Gómez-Rodríguez1, 3, 4 1

Dept. Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain Present address: Laboratory for nanostructured solar cells, International Iberian Nanotechnology Laboratory, Braga, Portugal. 3 Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid, Spain. 4 Instituto de Fisica de la materia Condensada IFIMAC, Universidad Autónoma de Madrid, Madrid, Spain. bruno.delatorre@uam.es 2

Abstract Since the discovery of the fascinating properties of free-standing graphene, the scientific community is devoting a huge effort in exploring, both experimentally and theoretically, this true two dimensional material (1). The growth of graphene on metals is being thoroughly investigated both from a perspective focussed on applications, as large-scale monolayer graphene with low defect density can be prepared, (2) as well as from a fundamental point of view, due to the strong substrate-dependent differences found on graphene-metal interactions (3). Scanning tunneling microscopy (STM) is an ideal approximation to study the atomic-scale electronic properties of graphene (4). However, understanding the atomic structure is rather complicated because of the sensitivity of STM to the local density states near the Fermi level. Noncontact Atomic Force Microscopy (NC-AFM) in Frequency Modulation (FM) mode, where a frequency shift (f) from the cantilever resonance frequency at free oscillation is detected, arise as an ideal complementary approach for studying graphene atomic structure on metals since it is a technique sensitive to the interaction force between the tip apex and the outermost sample atoms, which can also lead to very high spatial resolutions (5). In this contribution, for the first time, NC-AFM measurements with atomic resolution of the graphene/Pt(111) system are reported. We have used a new home-made atomic force microscope operating under ultra-high vacuum conditions at low temperature (5K). Measurements using commercial platinum coated silicon cantilevers (Nanosensors NCL-Pt) show sharp contrast inversion at the atomic scale as the frequency shift is varied, changing from apparent hexagonal patterns (with only one maximum per unit cell) to honeycomb-type patterns (see Fig. 1). The different frequency shifts are related to different average tip-sample distances and, thus, to different interaction. Specific-site force spectroscopy has been used to clarify the relation between attractive and repulsive forces in the tipsample interaction involved in atomic contrast inversions. The present experimental results on graphene/Pt(111) are compared to previous measurements on graphene/Ir(111) by Bonenschanscher et al (6) as well as to density functional theory calculations by Ondrácek et al. (7), where it was discussed the origin of atomic resolution contrast inversions on free standing graphene in terms of different tip apex terminations. References [1] Novoselov K. S.; Geim A. K.; Morozov S. V.; Jiang D.; Katsnelson M. I.; Grigorieva I. V.; Dubonos S. V. & Firsov A. A., Nature, 438 (2005) 197–200. [2] Li X.; Cai W,; An J,; Kim S,; Nah J,; Yang D,; Piner R,; Velamakanni A,; Jung I,; Tutuc E,; Banerjee S. K.; Colombo L.; Ruoff1 R. S., Science, 324 (2009) 1312–1314. [3] Wintterlin, J. & Bocquet, M. L., Surf. Sci. 603 (2009) 1841–1852. [4] Ugeda,M.; Fernández-Torre,D.; Brihuega, I.; Pou, P.;Martínez-Galera, A.; Pérez, R.; GómezRodríguez, J.M., Phys. Rev. Lett.,107 (2011) 116803. [5] Gross, L.; Mohn, F.; Moll, N.; Liljeroth, P.; Meyer, G. Science 325 (2009) 110. [6] Boneschanscher M. P.; van der Lit J.; Sun Z.; Swart I.; Liljeroth P.; Vanmaekelbergh† D., ACS Nano, 6 (2012) 10216–1022. [7] Ondrácek, M.; Pou, P.; Rozsíval, V.; González, C.; Jelínek, P.;Pérez, R.Phys. Rev. Lett., 106 (2011) 176101. [8] Horcas, I.; Fernández, R.; Gómez-Rodríguez, J.M.; Colchero, J.; Gómez-Herrero, J.; Baró, A.M. Rev. Sci. Instrum. 78 (2007) 013705.

Figures

Fig 1. 6x6nm2 simultaneously recorded atomic resolution NC-AFM images on Graphene/Pt(111); a) Topography image at a set point ď &#x201E;f = -72Hz. A hexagonal lattice with only one maximum per unit cell is observed; b) Simultaneously recorded image at a lower (in absolute value) set point ď &#x201E;f = -62Hz where a honeycomb pattern is detected. Both images were taken using the retrace technique with the WSxM software (8). Oscillation amplitude: 20nm, bias voltage: 0V.

New results on Extraordinary Transmission at infrared and optical frequencies. Vicente Delgado, Ricardo Marqués and Lukas Jelinek Department of Electronics and Electromagnetism, Av. Reina Mercedes 41012, Seville, Spain vdelgado@us.es Abstract In recent papers [1]-[3] the authors presented quasi-analytical surface impedance and transverse waveguide analysis models for the characterization of Extraordinary Transmission (ET) through screens with a periodic array of subwavelength holes. At the present time, the ET phenomenon or diffraction by arrays of holes in general are in the edge of potential applications in optical sensors [4] or solar cells concentrators [5]. Despite the increasing strength of computers, numerical model can still provide fastest characterization and gain physical insight. In this contribution new interesting results will be presented including the intermediate regime between ET and fishnet metamaterial (FM) potential applications of ET screens in molecular spectroscopy with angle tuning or refraction of Gaussian beams. In Fig.1 transmission through 1, 2, 4, 8 and 16 screens is calculated and validated through full wave simulations. Dispersion diagram corresponding to an infinite stack is also shown. With only a few screens the transmission band forms as a superposition of individual resonances. Amplitude of the band does not decrease substantially with the number of screens. Thus, it seems that losses are not a limiting factor in fishnet metamaterials at optical frequencies. Gaussian beams can be decomposed in terms of plane waves. The behavior of Gaussian beams passing through a stack of four arrays of screens at different frequencies and with different polarizations is shown in Fig.2. In case of incidence TM wave, the transmitted beam is always refracted towards positive values whereas in case of an incident TE beam the shift is positive or negative depending on the angle of incidence. This can be explained in terms of the transverse waveguide theory. For TM incidence it is always the backward to the excitation TM0-1 mode the dominant one, whereas for TE incidence the dominant mode change with the angle of incidence. For angles smaller than 26.57º it is the forward excited TM01 mode the dominant one and for angles greater than 26.57 it is the backward TM1-1 mode the dominant one. Finally, we have simulated screens with the same parameters as the hole arrays in [2] except for the periodicity (7 μm) (see Fig.3). The problem is scaled to mid infrared frequencies. It is expected that when the frequency of operation of the screen coincides with some absorption frequency of the molecule to be detected, a change in the amplitude and position of the peak could be used as a detection mechanism [6]. References [1] F. Medina et al. IEEE-MTT, vol. 56, p. 3108, 2008. [2] V. Delgado et al. Optics Express, vol. 18, p. 6506, 2010. [3] V. Delgado et al. IEEE-AP, vol. 61, p. 1342, 2013. [4] A.A. Yanik et al. Nano Letters, vol. 10, p. 4962, 2010. [5] S.Y. Chou and W. Ding, Optics Express, vol. 21, p. 61, 2013. [6] S. M. Williams et al., Applied Physics Letters, vol. 107, p. 11871, 2003.

Figures

Fig. 1: Transmittance through 1, 2, 4, 8 and 16 silver screen with a periodic square array of square holes (in plane periodicities are 1μm, transversal periodicity is 100 nm and size of the holes is 250 nm) .Dispersion diagrams with normalized phase and attenuation constants corresponding to an infinite array of screens is shown below. In the transmittance spectra, continuous lines correspond to our model and dotted lines to CST simulations. In the dispersion diagrams the continuous line corresponds to the normalized phase constant and dotted line to the normalized attenuation constant; both calculated with our model.

Fig. 2: Field amplitudes computed at the output plane of Gaussian beams impinging at different angles of incidence and passing through silver screens. In (a) field profiles correspond to the transmitted TM and in (b) to TE beams for different angles of incidence. For each angle of incidence, the fields are calculated at the frequency of the maximum transmission: 230.3, 204.5, 184.5 and 169.6 THz for incident beams with TM polarization (a) at 10, 20,30 and 40º; and 265.0, 274.5 288.6 and 281.6 THz for incident beams with TE polarization (b) at 10, 20, 30 and 40º. The input and output planes are placed 10 μm away from the central plane of the structure.

Fig. 3: Transmission through an array of square holes in an gold screen deposited on a adhesive titanium layer and a silicon nitride substrate under oblique TM incidence. Periodicity is 7m, size of the holes is 3m and thicknesses of the gold, titanium and substrate layers are 150, 5 and 70 nm respectively. Angle-tuning seems feasible in mid-infrared spectroscopic applications with arrays of holes. Continuous lines (a) correspond to our numerical model and dashed lines (b) to CST simulations.

1) 2)

ASPHALTENES AS OBJECTS OF NANOELECTRONICS 1,2) 1) , 2) 1) Dolomatov M.Yu. , Dezortsev S.V. Bakhtizin R.Z. , Shulyakovskaya D.O. , 1) 2) 1) Dolomatova M.M. , Kharisov B.R. , Eremina S.A. Ufa State University of Economics and Service, Dep. of physics, Chernyshevsky st. 145, 450078 Ufa, Russia Bashkir State University, Dep. of physical electronics and nanophysics, Zaki Validi st. 32, 450074 Ufa, Russia

Contact@E-mail Dolomatov@gmail.com Abstract Modern carbon nanomaterials are expensive products of difficult technology (carbon nanotubes, graphenes, fullerenes, polycyclic molecules). Therefore search of new cheap materials on the basis of natural substances, in particular high-molecular compounds of oil – asphaltenes, is actual for nanoelectronics, Asphaltenes are complex substances that are found in grude oil, bitumen and high-boiling hydrocarbons distillates [1]. Asphaltenes are composed mainly of polyaromatic carbon with vanadium and nickel traces, which are in porphyrin structures. Molecules of asphaltenes may contain 5-10member benzene and naphthenic rings in their structure. Asphaltenes have paramagnetic centers. We had the research task to define electron, molecular and supramolecular structure of various asphaltenes. Experimental methods of electronic phenomenological spectroscopy (EPS), atomic force microscopy (AFM) and quantum chemistry were used to definite the structure of oil asphaltenes. EPS was proposed first by Dolomatov et al. [2]. Unlike conventional method, EPS studies substances as a single whole without separating it’s spectrum into characteristic frequencies of individual functional groups and components of the radiation absorbing system. The EPS is based on the regularities of the relations between the absorption coefficients and electronic properties of the substance. Effective Ionization potential (EIP) and effective electron affinity (EEA) of asphaltenes have been estimated according to empirical dependences linking these characteristics with integral force of oscillator θ (1) and (2) in UV and/or VIS spectrum regions under consideration:

E  1   2 ,

(1)

 

2

 

 f (ε

)ddλ

(2)

where Е is effective ionization potential or effective electron affinity, eV; α1, α2 are empirically determined -1 -1 coefficients, eV and eV·mole·l ·nm respectively; λ is molar absorption coefficient; 1, 2 are borders of wavelengths in the spectrum in UV and (or) visible regions. It was revealed, during the origin data study of different asphaltenes and hydrocarbon systems (Table 1,2), that asphaltene fraction is a strong electron donor and acceptor at the same time (IP=4.375.70 eV, EA=1.85-2.50 eV). This means, that the processes in asphaltenes solutions and concentrates, including those related to ARPD (asphalt, resin and paraffin deposits), may be described by the formation of molecular charge-transfer complexes. Таble 1. Donor-acceptor properties of asphaltenes and resins by the EPS data Asphaltenes EIP, eV EEA, eV Forbidden Imref, eV gap, eV Asphaltenes and resins of Radaevsk 5.70 1.85 3.85 1.93 oilfield Asphaltenes of Surgut oilfield 5.20-5.70 2.10-2.50 3.10-3.20 1.55-1.60 Asphaltenes of strait-run stoks 4.37-5.27 2.44-2.50 1.93-2.77 0.96-1.38 Asphaltenes of tar 4.70-4.90 2.10-2.15 2.60-2.75 1.30-1.38 Asphaltenes of Kushkul oilfield 5.20 1.90 3.30 1.65 Table 2. Electronic structure data of the semiconductors on the base of resins and asphaltenes (paramagnetic phase) Semiconductors on the Physical-chemical property base of natural Effective Effective Imref, eV Concentration of Molecular polycyclic hydrocarbons ionization electron paramagnetic centers weight, potential, affinity, eV (carbon free radicals), а.m.u. 18 3 eV 10 ·spin/sm Asphaltenes of high4,72-4,74 1,83-1,84 1,45-1,45 156-222 2394-3125 boiling distillates* Asphaltenes, heat4,71-4,74 1,83-1,84 1,44-1,45 159-172 2733-3280 treated, Т=400 °С * Asphaltenes of west 4,72-4,94 1,83-1,95 1,45-1,50 44-139 980-2671 Siberian oil deposits Oil asphaltenes** 4,72-4,77 1,83-1,86 1,45-1,46 203-218 1870-2295 Oil resins 4,95-5,14 1,96-2,06 1,50-1,54 19-90 464-782 * obtained by Dezortsev S.V.

** obtained after the manner of Hayrudinov I.R. ** The structures of asphaltenes model fragments were calculated by RHF 3-21G , 6-31G** methods [3]. The earlier made assumption, that paramagnetic phase of oil asphaltenes belongs to amorphous, compensated, wideband semiconductors is confirmed. AFM study of asphaltenes obtained from crude oil showed the presence of structure fragments ranged from 3 nm to 10 nm, disposed to strong intermolecular interactions. We used different doped compounds for formation of wide gap amorphous semiconductors from a concentrates of asphaltens. Thus paramagnetic phase of asphaltenes can be used as available semiconductors for nanoelectronics. Таble 3. Computed and experimental ranges of IP and EA Data IP, eV EA, eV By UV and VIS spectrums 4.37-5.70 1.85-2.50 Computed molecular fragments (RHF/3-21G** method) 6.36-7.56 0.54-1.65 IP and EA estimation of free-radical fragments 4.92-5.79 1.78-2.45 The calculations results are confirmed by the EPS spectroscopic data (Таble 3). According to the experimental estimates, IP values are in the range from 4.37 to 5.70 eV, EA - in the range from 1.85 to 2.50 eV. Thus, the best agreement with the experiment is observed for the free radical fragments. Quantum-chemical calculations of molecular and radical fragments with total geometry optimization by molecular mechanics and methods 6-31G** display that the structure of naphthenoaromatic fragments of asphaltenes is nonplanar and has a “bowl” form (Fig. 1). The computing of condensed model asphaltene structures shows, that in extreme case of total aromatization of all rings condensed asphaltene fragment have the “plate” structure (Fig. 1). Studies of the supramolecular structure of asphaltenes by AFM [3] found that molecular structure of objects with a resolution of about 1 micron is a quasi-gel-like structure consisting of micelleassociated asphaltene molecules. The average concentration of particles in the dispersed phase is 144 2 particles per 1 μm . A more detailed analysis at a resolution of 500 nm (Fig. 3) shows that the distance between the micelles is about 20-50 nm. The thickness of the particle diameter of 100 nm is less than 3 nm, indicating that stacking structures. This means the association of molecular fragments in the complex structural units, which confirms the view Unger F.G. on the associative stacking structure of particles petroleum asphaltenes. The main conclusion of the reaseach is that paramagnetic phase of asphaltenes is organic amorphous broadband semiconductor and can find application as cheap nature material in nanoelectronics. References [1] Dolomatov M.Yu, Dezortsev S.V., Shutkova S.A., Journal of Materials Science and Engineering, No.2 (2012), p.151-157. [2] Dolomatov M.Yu., Mukaeva G.R., Shulyakovskaya D.O.,Journal of Materials Science and Engineering B, No.3 (2013),p.183-199. [3] M.Yu. Dolomatov, S.V. Dezortsev, R.Z. Bakhtizin, S.A. Shutkova, D.O. Shulyakovskaya, N.Kh. Paymurzina About possible formation of organic semiconductors from paramagnetic phase of asphaltenes, ElecMol’12, France, Grenoble (2012), P. 160.

Figures

Fig. 1. Condensed models of the asphaltene structure fragments in the cases of total aromatization of the rings and double bonds full absence (“bowl”)

Fig. 2. Results of the supramolecular structure of asphaltenes AFM in detail: a-2D-format b-3Dformat

1) 2)

SPECIFIC QUANTUM INTERACTIONS IN THE MOLECULES AND NANOPARTICLES OF ORGANIC SEMICONDUCTORS 1,2) 2) 2) 1) Dolomatov M.Yu. , Paymurzina N.Kh. , Latypov K.F. , Mukaeva G.R. Bashkir State University, Dep. of physical electronics and nanophysics, Zaki Validi st. 32, 450074 Ufa, Russia Ufa State University of Economics and Service, Dep. of physics, Chernyshevsky st. 145, 450078 Ufa, Russia

e-mail: dolomatov@gmail.com Quantum calculating of electron structure of organic semiconductors in the form of many-electron systems – large molecules, polymers, structures of nanotube - type and fullerenes, based on the methods of density functional and Hartree – Fock is known to result in significant discrepancy between the predicted and experimental values. The attempts of enhancing the results at the expense of improving of interparticle potentials and expansion of the base of source wave functions seem to have trimming character and represent a mathematical technique of improving the result without having precise physical substantiation. Moreover, the task of searching for the wave function at most approximated to the experiment from the point of view of mathematics, which has infinite range of solutions, is not a proper task according to Adamar – Tikhonov. One of the reasons of falls-through of the existing methods, in the authors’ opinion, is the absence of precise notion concerning the correlation of collective movement of electrons and correlated interactions of outer and inner shell electrons. The aim of the research is experimental and theoretical research of the correlation of outer shell electrons and electrons of inner shell of molecules. Using the experiment, the research was conducted for quasi – independent electrons in Hartree – Fock approximation of electrons and atoms on the basis of experimental data on the energy of ionization. The objects of the research were the molecules of nitrogen – containing, oxygen – containing, aromatic hydrocarbons and the atoms of alkaline metals. Experiments, testifying to the correlation of outer and inner shells of atom and molecule electrons During the last decades in the works, carried out under the guidance of Dolomatov M.Yu., the regularities testifying the interaction of outer and inner atom shells have been developed [1,2]. The connections between the energies of electron ionization and the energies of aggregation of electron states which are expressed by the integral strength of the oscillator have been ascertained. (ISO). Е   1   2 lg (1);  lg  lg(  ) d , (2)



where Е – the energy of boundary orbitals, IP, eV; ( 1 ,  2 ) –empirical coefficients, dependent on the type of an -1 orbital, constant in the given homologous series, correspondingly eV, eV ·nm ;  lg – integral logarithmic indicator of absorption (logarithmic ISO), nm;   f ( ) – corresponding spectral function of electromagnetic radiation absorption for atoms and molecules; where ε – molar coefficient of absorption, dimensionality, accepted in -1 -1 -1 2 -1 electron spectroscopy, mol/l ·cm , in SM 10 ·m ·mol . As it follows from the research [1,2], the dependence (1) has universal character, as ISO characterizes the aggregation of all the states of electrons absorbing energy in UV and visible region, we can surmise the correlation between the outer and inner electrons. The results are corroborated by the investigation of the second and third IP of the atoms of alkaline metals, defined by the method of photoelectron spectroscopy. (3) p1  A1  A2 p2 ; p2  A3  A4 p3 Where A1-A4 –coefficients which depend on the nature of substances; p1, p2, p3-first, second and third IP. Statistic estimation of electron correlation in atom and molecular systems with statistic methods applied

Polycyclic aromatic hydrocarbons, containing from two to five annelated benzene rings, nitrogen containing compounds series of acridine, pyridine, peredazone, quinoline, amine, indole and have been chosen as the object of the investigation. ** The non empirical method of Hartree – Fock in simple Gaussian basis RHF-3-21G has been chosen as the method of calculating energy of MO. The calculations have been carried out with the full optimization of the geometry of molecules. The distribution of the electron energy for many-electron systems is defined by the system of integro – differential equations in Hartree – Fock approximation: where F – matrix of Fock, i – energy of MO. (4) Fi   i i , The effect of correlation between the first vertical IP and the energies of deep MO are presented as a linear matrix equation:   i1   1      i2   1  ...    ...       1  im  

 p11    i1      p12   1i    i 2  ,    ...   2i   ...        p1m   im 

(5)

where ij – the element of column – matrix, which corresponds to the energy of i MO of j- compound; 1i– the energy of i MO under p1j=0; 2i – the coefficient which characterizes the change of energy of i MO in the conditions of increasing the energy of the corresponding level by 1eV; p1j – the experimental first vertical IP of j

compound; ij – the parameter of disturbance, which takes account of the deviation ij from the mean value, i=2..n, j=1..m. As the measure of electron interaction of electron quant states (the levels of the energies of ionization), the statistic coefficient of linear correlation, which for all the systems of electron levels is expressed by the matrix correlation, has been used R For example the results of the research testify that in the lines of aromatic hydrocarbons the second (r=0,38), the third (r=0,25), the twelfth (r=0,24), the forty-seventh (r=0,23) energy levels have the maximum influence on the first vertical IP. (Fig.1). In the lines of nitrogen – containing compounds in the frame of RHF-6-31G** method the levels 2 (r=0,88), 5 (r=0,83), 8 (r=0,76), 10 (r=0,75), 12 (r=0,68) have the maximum influence on the first vertical IP; the levels 3 (r=0,78), 4 (r=0,79), 6 (r=0,76), 9 (r=0,76), 10 (r=0,76), 11 (r=0,66), 13 (r=0,66), 14 (r=0,65) have the minimal influence. In all the correlations of 15 MO, which cover the whole line of nitrous compounds (according to the number of occupied pyrites MO – the least compound in the line), have been considered. In Fig. 2 the th graphic dependence of the first vertical IP on the deep MO (down to the 15 level) is shown. [3]. Evidently, the obtained effects of electron correlation can be explained by the effects of quantum correlation and quantum entanglement of electrons, which have been investigated by Zeilinger [4-6]. So, in the molecules of polycyclic semiconductors the effects of correlative interaction of high and deep molecular levels considerably appear, therefore, such important physical characteristics as ionization energy, the work of electron yield, the level of Fermi semiconductors is in great extent determined by correlative effects. Evidently, such phenomena as the influence of outer electrons on K – capture of inner electrons by atom nuclei can be explained by such correlations. In respect to chemical interactions we can note that the energies of chemical reaction activation will be defined by the whole system of molecular electrons, but not only by valent electrons. The construction of correlated diagrams will allow to forecast the degree of influence of low energy levels on physical and chemical processes in complex information quantum molecular systems. The investigation of the dependence of the first ionization energy on the energy of deep electrons has great significance for molecular electronics. The research conducted shows that this influence is defined by the whole electronic system; therefore, the inner shell of atomic and molecular core considerably influences the work of electron yield and the width of the forbidden band in organic semiconductors. References [1] Dolomatov M.Yu. Mukaeva G.R., Journal Applied spectroscopy. (1992). V.56. N4. p.570-574. [2] Dolomatov M.Yu., Mukaeva G.R., Shulyakovskaya D.O., Journal of Materials Science and Engineering B, (2013). – Vol.3.- №3.-P. 183-199. 17,0 с. [3] Dolomatov M.Yu., Latypov K.F., ElecMol’12, France, Grenoble, (2012). P. 229. [4] Hackermueller L., Hornberger K., Brezger B., Zeilinger A. and Arndt M., Nature 427, (2004), с. 711-714. [5] Bennett C. H., Brassard G., Crépeau C., Jozsa R., Peres A., Wootters W. K., Phys. Rev. Lett, (1993). V. 70, p.18951899. [6] Volovich I.V. - Podolsky – Rosen. M., (2002).P.33-35.

Correlation coefficient, R

Figures

Energy level

Fig.1 The correlation of the aggregate of quantum states in the series of organic semiconductors on the basis of polycyclic molecules for the first MO.

Energy level

Fig.2. The dependence of the experimental first vertical PI on the energy of deep orbitals.

Synthesis and preparation of magnetic core-shell nano-composites with bioactive glassy material

Domingues, R.Z , Andrade, A.L. , Fabris, J.D. , Ferreira, J.M.F. . a

Department of Chemistry-ICEX, Federal University of Minas Gerais (UFMG), 31270-901 Belo Horizonte, Brazil.

Department of Chemistry, Federal University of Ouro Preto (UFOP), 35400-000, Ouro Preto, Brazil

Federal University of Jequitinhonha and Mucuri Valleys (UFVJM), 39100-000, Diamantina, Brazil d

Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal rosanazd@yahoo.com.br

Introduction Core-shell nano-composites of magnetic cores coated with bioactive or multifunctional shell layers of materials such as mesoporous silica, carbon, collagen and lipid have drawn a great deal of efforts on the development of new materials destined to be used in (i) medical procedures based on hyperthermia, in oncology, (ii) magnetic bioseparations and (iii) magnetic resonance imagery. In the present study, magnetic nanoparticles were synthesized by precipitation and then dispersed with tetramethylammonium hydroxide. The dispersed nanoparticles were used as core material to prepare core-shell composites by coating them with sol-gel derived bioactive glasses of different chemical compositions. The glasses were prepared through hydrolysis and polycondensation of tetraethyl orthosilicate, triethyl phosphate, and Ca(NO3)2.4H2O. The silica contents of these two glass-coated samples were found to be 63 mass% (sample BG63) and 85 mass% SiO2 (BG85). The in vitro biomineralization activity of the bioactive glass coatings were evaluated by immersing the samples in simulated body fluid (SBF). Results revealed that although both shells are bioactive and became coated with an apatite-like layer after 15 days soaking in SBF, the mineralization process was found to be faster for sample BG63. These nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy; X-ray diffraction and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Results ATR-FTIR spectroscopy data were used to evaluate changes occurring at the surface of these coreshell particles as a function of soaking time. Figs. 1a and 2a show the characteristic bands assigned to -1 Si-O bonds for the BG63 and BG85 samples heat-treated at 700 ยบC. The bands at 640, and 570 cm -1 correspond to maghemite. The band at 450 cm corresponds to Si-O and Fe-O bonds. Clear changes can be observed in the spectra of the BG63 and BG85 samples after 7, 14 and 21 days soaking in SBF (Figs. 1b-d and 2b-d), respectively. After 14 days soaking in SBF, transmittance bands of the phosphate groups do appear, together with those of the carbonate groups, well in accordance with the characteristic FTIR spectrum for hydroxycarbonated apatite.

Fig. 1. ATR-FTIR spectra of BG63 heat-treated at 700 ยบC, before (a), and after immersion in SBF for: 7 days (b); 14 days (c); 21 days (d).

Fig. 2. ATR-FTIR spectra of BG85 heat-treated at 700ยบC, before (a), and after immersion in SBF for: 7 days (b); 14 days (c); 21 days (d).

Conclusion The magnetic core nanoparticles were efficiently coated with bioglass shells by a sol-gel approach conferring them a hydrophilic character. The in vitro studies in SBF aimed at predicting the in vivo mineralization behaviour of the bioglass coated magnetic nanoparticles. They revealed that the formation of a hydroxycarbonate apatite-like layer occurred in both systems, being somewhat faster when the shell layer is less rich in silica. Keywords: Magnetic nanoparticles; Mรถssbauer spectroscopy; hyperthermia.

Acknowledgments: Work financially supported by CNPq FAPEMIG and CAPES (Brazil).

Fabrication and fluorescence analysis of biofunctionalized gold quantum dots array Jana Drbohlavova, Radim Hrdy, Marek Bedlek, Vojtech Svatos, Alexander Mozalev, Lukas Kalina, Jaromir Hubalek Brno University of Technology, Central European Institute of Technology, Technicka 3058/10, 616 00 Brno, Czech Republic drbohla@feec.vutbr.cz Abstract The development of new biosensors with the help of micro- and nano-scale technologies allows the improvement of current medicinal diagnostic and therapeutic methods. Optical biosensors represent a broad group of tools based on luminescence, fluorescence, colorimetry or interferometry. These sensors, which are both very sensitive and selective, have found numerous applications, mainly in in vivo and in vitro imaging [1]. In vitro optical biosensing of proteins and nucleic acids based on fluorescence detection can be easily achieved using quantum dots array. In general, various materials including semiconductor oxide or noble metals are used for the creation of quantum dots strongly fixed on solid substrates [2]. Gold belong to the most studied material due to its attractive fluorescent and plasmonic properties [3]. Selfordered gold quantum dots array can be readily created via gold pulse galvanic deposition onto prepatterned surface. This non-lithographic template based process of fabrication is cheap, rapid and well reproducible [4]. The method is based on the formation of nanoporous anodic aluminium oxide (AAO) template on tungsten nanolayer, which is transformed into tungsten oxide nanostructures (see Figure 1 a-e). In the following step, these WO3 nanostructures are selectively removed from AAO template in chemical etching process which results in the creation of nanodimpled surface. Finally, gold is electrodeposited trough AAO template into self-ordered dimples. After AAO template selective dissolving, gold quantum dots with tunable size and strong adhesion to substrate are formed. The complex of fabrication conditions, such as current density, electrolyte composition, concentration, and temperature, and duration and number of deposition pulses as well as a period between each pulse significantly influence the final QDs dimensions and ordering. All these parameters have to be taken into account regarding the achievement of homogenous coverage of surface with QDs having uniform size distribution. The surface roughness of pure metal layers before anodization process is measured using profilometer. Ordering and size of Au QDs are analyzed using SEM (see Figure 2). The influence of vacuum annealing on Au QDs crystallinity is also studied. The chemical composition of Au QDs is characterized using EDX and XPS. The fluorescence correlation spectroscopy and stationary polarized fluorescence were used for the study of Au QDs array optical properties before and after biofunctionalization. Two biomolecules, namely glutathione (GSH) tripeptide and bovine serum albumin (BSA) protein, were chosen as model compounds for Au QDs modification. The surface immobilization of these biocomponents is done by means of physical adsorption. These ligands can further serve as binding partner for detected analyte in the solution. References [1] Fracchiolla N. S., Artuso S., Cortelezzi A., Sensors, 13 (2013) 6423. [2] Drbohlavova J., Vorozhtsova M., Hrdy R., Kizek R., Salyk O., Hubalek J., Nanoscale Research Letters, 7 (2012) 123. [3] Ng V. W. K., Berti R., Lesage F., Kakkar A., Journal of Materials Chemistry B, 1 (2013) 9. [4] Calavia R., Mozalev A., Vazquez R., Gracia I., Cane C., Ionescu R., Llobet E., Sensors and Actuators B-Chemical, 149 (2010) 352.

Figures

Figure 1 Fabrication of self-ordered Au QDs array: a) thermal-evaporated aluminium layer (light blue) on sputter-deposited tungsten layer (blue) on silicon wafer; b) anodic oxidation of aluminium layer into alumina nanoporous template (green); c) anodic oxidation of tungsten layer into tungsten trioxide forming ordered nanodots on the pores bottom (black); d) self-ordered nanodimples after tungsten trioxide nanodots removing; e) gold nanodots galvanically deposited into the dimples through alumina template.

Figure 2 SEM figures of self-ordered Au QDs array prepared under 5 pulses and deposition time of 250 ms (left); 15 pulses and deposition time of 100 ms (center); and 15 pulses and deposition time of 200 ms (right). The estimated size of Au QDs varies from 10 to 30 nm depending on the preparation conditions.

Effect of Ethanol on Self-assembly of SbpA Surface Layer Protein Roman Dronov, Joseph G. Shapter, Scott McCormick School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA 5042, Australia roman.dronov@flinders.edu.au Abstract

Bacterial cell surface layers (S-layers) are found on the cell envelope component of many bacteria and archaea. S-layers are made up of protein subunits which form a protective crystalline lattice at the outer cell wall. S-layers have attracted much interest in the scientific community due to their ability to self-assemble and produce supramolecular arrangements at the Nanoscale [1]. SbpA is a relatively well-studied S-layer protein and is a promising material for surface functionalization in biosensors and biofuel cells [2, 3]. In many of such applications it is exposed to solutions that have aggressive components with an effect on the proteinâ&#x20AC;&#x2122;s conformation. It is, therefore, important to verify the explicit effects of sample components that are potentially damaging to the protein layer, such as ethanol. The aim of the present study was: (i) to test the effects of exposure to different amounts of ethanol of a readily recrystallised S-layer; and (ii) check the influence of ethanol at low concentrations added during the S-layer recrystallization phase. The latter is of interest as addition of ethanol can be used to tune the surface energy of the substrate, in this way acting as a surfactant. SbpA recrystallisation has been carried out on silicon following the procedure reported by Vollenkle et al [2]. Readily assembled protein coatings on silicon were exposed to a range of concentrations of ethanol for 1 hour, after which the surface was imaged by the Atomic Force Microscopy (AFM) in MilliQ water. It has been found that SbpA structure showed gradual deterioration following the ethanol concentration; however, it sustained the distinct island nature of the films until the concentrations of ethanol up to 40% were reached (Figure 1). At concentrations exceeding this amount the film morphology changed dramatically (Figure 1), possibly due to unfolding of the self-assembly domain. While the protein demonstrating unparalleled stability for ethanol exposure following the assembly, a different effect has been found when ethanol was added during the recrystallisation step. Here, additions of up to 5 % ethanol during the assembly stage did not interfere with the recrystallization process and in many cases resulted in better surface coverage and minimization of gaps between the islands (Figure 2). Exposure to higher ethanol content, in this case, quickly leads to the loss of the S-layer pattern and the crystallinity of the coating. These findings show promise in the use of SbpA as a substrate to create biosensors that can operate in the presence of ethanol. References [1] Sleytr, U., Messner, P., Pum, D., & Sara, M.. Angewandte Chemie 38 (1999) 1034-1054. [2] Vollenkle C, Weigert S, Ilk N, Egelseer E, Weber V, et al. Appl Environ Microbiol 70 (2004) 1514-21. [3] Ilk N, Vollenkle C, Egelseer EM, Breitwieser A, Sleytr UB, Sara M. Appl Environ Microbiol 68 (2002) 3251-60.

Figures

Figure 1. AFM images of SbpA layer assembled on silicon upon 1 hour exposure to ethanol: i) 10%, ii) 20%, iii) 30%, iv) 40%, v) 50%. Original images were acquired at 1x1 Âľm scan size.

Figure 2. AFM images of SbpA layer assembled on silicon with addition of ethanol to recrystallisation solution: i) 2.5%, ii) 5%, iii) 7.5%. Original images were acquired at 1x1 Âľm scan size.

Prussian blue nanoparticles as novel red-ox specie for sensitive label-free immunosensing using nanochannels: application to parathyroid hormone –related protein (PTHrP) detection Marisol Espinoza-Castañeda

, Alfredo de la Escosura-Muñiz1, Alejandro Chamorro1,2, Carmen de 2

1,3*

Torres , Arben Merkoçi ICN2 - Institut Català de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain. 2 Hospital Sant Joan de Déu, Paseo Sant Joan de Déu, 2, 08950 Esplugues de Llobregat, Barcelona, Spain. 3 ICREA - Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain *arben.merkoci@icn.cat

Abstract In this work the use of Prussian blue nanoparticles (PBNPs) as novel red-ox indicator agents for the improvement of the sensitivity of a label-free electrochemical immunosensing system based on nanoporous platforms is presented for the first time. Recently our group developed a protein [1,2] and DNA [3] an electrochemical detection technology based on solid-state nanochannel arrays with interest for rapid and cost-effective diagnosis tools [4].. The detection principle is based on the monitoring of 4[Fe(CN)6] diffusion through anodized aluminum oxide (AAO) membranes attached onto a screenprinted carbon electrotransducer and its differential pulse voltammetry signal change upon biomolecule recognition. However, the label-free methodology suffers of lack of sensitivity, probably due to the small 4size of the [Fe(CN)6] ions, which requires a high quantity of protein so as to be blocked making necessary sandwich based strategies, with inherent drawbacks in terms of time of analysis and reagents consumption beside its rather low efficiency for small proteins. For this reason, alternative redox indicators with bigger size than the ionic ones would be potentially useful for the improvement of the label-free approach. In this context, Prussian blue nanoparticles (PBNPs) appear as ideal candidates for this purpose. Stable and narrow-sized (around 4 nm) PBNPs, protected by Polyvinylpyrrolidone, exhibited a well-defined and reproducible red-ox pair and were successfully applied for the voltammetric evaluation of the nanochannels (20 nm pore sized) blockage due to the immunocomplex formation 4-/3(Figure 1). The bigger size of the PBNPs compared with ionic indicators such as the [Fe(CN) 6] system and the consequent increase in the steric effects which hinder their diffusion to the electrodes allows to improve the detection limits of model proteins (human IgG) from 200 µg/mL to 1 ng/mL levels. The sensitivity of the developed approach for the presence of small proteins captured inside the nanochannels is successfully applied for the detection of parathyroid hormone-related protein (PTHrP), a protein that exerts relevant functions in normal tissues and cancer, achieving its label-free detection at levels of 50 ng/mL.

References [1] De la Escosura-Muñiz, A., Merkoçi, A. Electrochemistry Communications 12, 2010, 859–863. [2] De la Escosura-Muñiz, A., Merkoçi, A. Small 7, 2011, 675–682. [3] De la Escosura-Muñiz, A., Merkoçi, A. Chemical Communications 46, 2010, 9007-9009. [4] De la Escosura-Muñiz, A., Merkoçi, A. ACS Nano 6 (9), 2012, 7556–7583.

Figures

B H2N-

-NH2 H2N-NH2 -NH2

H2N-

-NH2

H2N-

Figure 1. Schematic representation of the sensing principle. The formation of the immunocomplex blocks the diffusion of the Prussian Blue nanoparticles, giving rise to a decrease in their voltammetric signal.

Acknowledge We acknowledge MINECO (Madrid) for the project MAT2011-25870, the EU’s support under FP7 contract number 246513 ‘‘NADINE’’. Marisol Espinoza-C., acknowledge to Ministerio de Educación del Programa de Formación de Profesorado Universitario AP2010-5942. The authors also wish to thank Fundació Privada Cellex.

Determination of thiol traces in water samples based on the interaction between surfactant, hybrid magnetic core-shell nanospheres loaded with gold nanoparticles, and thiols Juan M. Fernández-Romero, Vanessa Román-Pizarro, Umair Gulzar, and Agustina Gómez-Hens Department of Analytical Chemistry. Institute of Fine Chemistry and Nanochemistry (IQFN-UCO) Campus de Rabanales. Marie Curie Building (Annex) University of Córdoba E-14071-Córdoba, Spain.Web: http://www.uco.es/investiga/ grupos/FQM-303. q52ropiv@uco.es Abstract An initial research about the development of a simple, rapid and selective fluorescence resonance energy transfer (FRET) system for the determination of thiols in environmental samples, involving the interaction between a surfactant, a phenol-formaldehyde core-shell magnetic-gold nanoparticle and the thiol is presented. The procedure involves the following steps: 1) Optimization of the synthesis procedure to obtain hybrid magnetic core-shell nanospheres loaded with gold nanoparticles (AuNPs), 2) Characterization by using spectroscopy and microscopy techniques, 3) Study of the potential reactivity between the nanospheres and different types of thiol compounds with special interest on forensic environmental pollutants, 4) Characterization of the propose methodology by definition of its analytical features and, finally 5) Validation of the proposed methods by their application to the analysis of real environmental samples. The FRET system consists of a Fe3O4 core, a luminescent phenolformaldehyde resin (PFR) shell, and AuNPs as FRET quenching agent, which were bound to the surface of the PFR shell. The luminescent Fe3O4@PFR spheres were exploited as donor, acting the AuNPs as acceptor. Different chemical systems in order to obtain an adequate local effective charge interaction between the surfactant/ Fe3O4@PFR@AuNPs nanospheres/thiol were tested, choosing sodium dodecylsulphate (SDS) for the development of the method.  

´



´

The Fe3O4@PFR spheres exhibit native fluorescence which is quenched by AuNPs, but it rapidly increases in the presence of thiolic compounds. Excitation and emission spectra where performed for different analytes, choosing 389 nm and 445 nm as excitation and emission wavelengths, respectively. The dynamic range of the calibration graphs developed using batch methodologies were established for eight thiolic compounds (homocysteine, thioglicolic acid, glutathione, dodecanethiol, cysteamine, -1 homocystine, cysteine and N-acetylcysteine) in the concentration range of 0.1 – 4000 µmol L , with -1 detection limits in the range between 0.06 to 0.71 µmol L . The precision of the method, expressed as relative standard deviation, ranged between 1.9 and 5.1 %. The method was applied to the determination of glutathione in underground water samples with recovery values ranging between 88.7 and 104.6 %.The proposed research will progress by studying dynamic approaches and extending their potential application in other areas included in forensic analysis.

Towards a new generation of ultra-dense magnetic memories: Organization, detection and manipulation of magnetic nanoparticles. a

A. Forment-Aliaga, E.Coronado, S. Kumar, E.Pinilla-Cienfuegos, S.Tatay, L.Català

Instituto de Ciencia Molecular (ICMol). Universidad de Valencia. b Catedrático José Beltrán Martínez nº 2, 46980, Paterna, Spain. Institut de Chimie Moléculaire et des Matériaux d’Orsay CNRS, Université Paris Sud 11, 91405 Orsay, France alicia.forment@uv.es

One of the last challenges in nanotechnology is to be able to organize, detect and manipulate individual nanometric magnetic units in order to prepare very high-density magnetic memory devices. These units can be, for example, magnetic nanoparticles (NPs) based on coordination chemistry compounds. The possibility of synthesizing a large family of NPs with different properties, based on one coordination compound, makes them really interesting.[1] At present we are working with NPs of a family of bimetallic cyanide-bridged coordination compounds known as Prussian blue analogues (PBA). PBA are molecule-based magnetic compounds of general formula AxMy[M’(CN6)]z (where A is an alkali-metal cation and M and M’ are transition metal ions) whose magnetism can be modified with an external perturbation.[2] In order to organize these anionic NPs, we take advantage of the electrostatic interactions with patterned silicon surfaces. We have used two different approaches: (i) Very local and precise nanolithography based on local oxidation by means of an atomic force microscope (LON-AFM), combined with the formation of self-assembled monolayers of different molecules on specific regions of the surface;[3] and (ii) Long range organization based on soft lithography with polydimethylsiloxane (PDMS) stamps. In this scenario we are able to attach PBA-NPs on the surface, as randomly disperse particles, at high accurate position on a specific point (few micrometers area), or in long periodic lines in square millimeters areas. The PBA-NPs have been magnetically characterized by low temperature magnetic force microscopy (LT-MFM). With this technique we obtain 3D topographic images and the magnetic image of the same region, measuring the interaction between a magnetic coated tip and each individual NP. Due to the possibilities of our setup, we can apply an external magnetic field with different magnitude and direction at different temperatures. This allows us to modify the magnetic orientation of the resultant magnetic moment of the NP and to detect it with nanometric resolution. The reversibility of NP magnetization with the external field proves that the signal that we are recording is purely magnetic and it is not masked by other long range interactions (for example electrostatic). [4]

References [1] L. Catala, F. Volatron, D. Brinzei, T. Mallah, Inorg. Chem, 8 (2009) 3360-3370. [2] Y. Prado, L. Lisnard, D. Heurtaux, G. Rogez, A. Gloter, O. Stéphan, N. Dia, E. Rivière, L. Catala, T. Mallah, Chem Commun, 3 (2011) 1051-1053. [3] E. Coronado , A. Forment-Aliaga , E. Pinilla-Cienfuegos , S. Tatay, L. Catala , J. A. Plaza, Adv. Funct. Mater. 17 (2012) 3625-3633. [4] C. S. Neves, P. Quaresma, P. V. Baptista, P. A. Carvalho, J.P. Araújo, E. Pereira, P. Eaton, Nanotechnology, 21 (2010) 305706.

Figure 1: Top: AFM topographic image of KxNi[Cr(CN)6]y NPs organized on a silicon surface with a softlithography method. Bottom: Magnetic images of the same region with different external magnetic field at -500 G, 0 G and +500 G (Color contrast indicates different magnetic interaction between tip and sample: Dark stands for attraction and bright for repulsion).

Stress induced and concentration dependent nitrogen diffusion in austenitic stainless steel Arvaidas Galdikas, Teresa Moskaliovienė Physics Department, Kaunas University of Technology, Studentų 50, LT-51368 Kaunas, Lithuania arvaidas.galdikas@ktu.lt Abstract A novel mass transport model of nitrogen atoms in austenitic stainless steels (ASS) taking place during plasma nitriding at moderate temperatures (below nitrides formation) is proposed. The model considers diffusion of nitrogen in presence of internal stresses as driving force of diffusion, i.e. this model is developed taking into account the stress – diffusion interaction during the nitriding process of ASS. Nitrogen diffusion in ASS is a complicated process and still not fully understood. The nitrogen depth profiles in nitrided ASS exhibit plateau-type shapes slowly decreasing from the surface, followed by a rather sharp leading edge, which cannot be explained by the simple Fick’s diffusion laws. In addition, the nitrogen diffusivity is faster than expected from classical diffusion. Commonly trapping and detrapping (TD model) effects are used to explain the plateau shape of nitrogen depth profile and the high diffusivity in nitrided ASS [1, 2, 3]. While in this work it was shown that internal stress induced diffusion is responsible for plateau formation in nitrogen depth profile which is characteristic for nitriding process. Furthermore, the nitrogen concentration and internal stresses gradients are the driving forces of fast (with unusually high diffusion coefficient) nitrogen diffusion. Thus, proposed nitrogen stress induced diffusion model can be as an alternative to the TD model. The applicability of the proposed stress–induced diffusion model was checked and proved for different types of austenitic stainless steel (1Cr18Ni9Ti and AISI 316L – see Fig.1 and Fig. 2, respectively) nitrided with different experimental conditions (temperature, time, flux of nitrogen; experimental results were taken from Ref. [4] and [5]). By fitting of experimental nitrogen depth profiles it was found that nitrogen diffusion coefficient in ASS during plasma nitriding vary with nitrogen concentration according to Einstein–Smoluchowski relation D(CN) = f(1/CN) (see Fig. 3). Furthermore, it was shown that swelling (or surface expansion, i.e. a change in linear dimensions of the modified region) has significant influence to the nitrogen distribution in plasma nitrided AISI 316L steel. Thus the main processes which occur during plasma nitriding of ASS below temperatures of nitrides formation are nitrogen concentration gradient and internal stress induced diffusion with concentration dependent diffusion coefficient and also swelling. Including those processes into kinetic differential equations gives not only good fitting of nitrogen depth profiles for different nitriding time samples, but also calculated swelling values very good correspond with experimentally measured ones (see Fig. 4; experimental points were taken from Ref. [6]). This aspect proves that diffusion model based on influence of internal stresses as a driving force for diffusion works good and explains nitriding process and nitrogen penetration mechanisms in stainless steel. In our previous works Refs. [7], [8] and [9] the detailed description of proposed stress induced nitrogen diffusion model with a concentration independent diffusion coefficient and numerical solution of the diffusion kinetic differential equations are presented. The dependencies of nitrogen flux, nitriding time and nitriding temperature on nitrogen concentration, nitrogen surface concentration and penetration depth are analyzed by proposed model. It is shown that, with the increase of nitriding time and temperature the compositionally-induced stresses and thickness of stressed steel layer increases. An interpretation of the modelling results showed that the nitrogen diffusion coefficient in nitrided ASS obeys the Arrhenius’ law. References [1] S. Parascandola, W. Moller, D. L. Williamson, Applied Physics Letters, 76 (2000) 2194. [2] A. Martinavičius, G. Abrasonis, W. Möller, C. Templier, J. P. Rivière, A. Declémy, Y. Chumlyakov, Journal of Applied Physics, 105 (2009) 093502. [3] T. Moskalioviene, A. Galdikas, J. Riviere, L. Pichon, Surface and Coatings Technology, 205 (2011) 0257–8972. [4] M. K. Lei, X. M. Zhu, Surface and Coatings Technology, 193 (2005) 22. [5] C. Templier, J.C. Stinville, P. Villechaise, P.O. Renault, G. Abrasonis, J.P. Rivière, A. Martinavičius, M. Drouet, Surface and Coatings Technology, 204 (2010) 2551–2558. [6] J. C. Stinville, C. Templier, P. Villechaise, L. Pichon, Journal of Materials Science, 46 (2011) 5503– 5511. [7] A. Galdikas, T. Moskalioviene, Computational Materials Science, 50 (2010) 796–799. [8] A. Galdikas, T. Moskalioviene, Surface and Coatings Technology, 205 (2011) 3742–3746. [9] T. Moskalioviene, A. Galdikas, Vacuum, 86 (2012) 1552–1557.

Figures

Fig. 1. Experimental points from Ref. [4] and calculated depth profiles of nitrogen after plasma nitriding (for 4 h at temperature 380 째C and at two 2 different nitrogen ion current densities 0.44 mA/cm 2 and 0.63 mA/cm ) of austenitic stainless steel 1Cr18Ni9Ti.

Fig. 3. The linear dependence of D(CN) ~ (1/CN) for plasma nitrided AISI 316L at different nitriding times without swelling (case (a)) and with swelling (case (b)).

Fig. 2. Experimental points from Ref. [5] and calculated (by stress induced nitrogen diffusion model with D(CN) and taking into account swelling process) depth profiles of nitrogen after plasma nitriding of austenitic stainless steel AISI 316L at 400 째C for 1, 3 and 8 hours.

Fig. 4. Experimental points form Ref. [6] and calculated (extracted from fitted data) values of swelling thickness and swelling rate.

Size dependence of Young’s modulus of metallic nanowires 1

S. Peláez , P. García-Mochales and P. A. Serena

Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMM-CSIC), C/Sor Juana Inés de la Cruz 3, Cantoblanco, E-28049-Madrid, Spain 2 Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid (UAM), C/Tomás y Valiente 7, Cantoblanco, 28049-Madrid, Spain pedro.garciamochales@uam.es Abstract Metallic nanowires are a system of great technological importance because of their potential applications in nanoscale electronics, photonics, biological and chemical sensors and resonators. A proper understanding of the size dependence of their Young’s modulus will lead further in our way to tailor their mechanical properties for practical applications. Although there are several previous studies that deal with the elastic properties of NWs, this issue requires an additional effort in order to systematically describe the dependence of the Young’s modulus with NW parameters such as size, external facets, etc. In this paper Young’s moduli E of different Al, Cu and Ni ultra-thin infinite nanowires are computed using Molecular Dynamics (MD) simulations, using the Embedded Atom Method (EAM) to describe the interatomic interactions [1]. We have considered an extended set of Al, Cu and Ni nanowires configurations to analyze the dependence of the Young’s modulus E with the nanowire orientation, cross sectional shape and thickness (Figure 1). We also study the character of the stress-strain response in these systems in the elastic phase. Maps of the spatial distribution of the atomic stress inside the nanowire (Figure 2) and its variation with the strain help us to understand the variation of E with the different nanowires parameters; also allows us to calculate the “atomic Young’s moduli”. Our results demonstrate that the elastic properties of these systems are bulk dominated: Nanowires (NWs) having different cross sectional shapes but the same axial orientation exhibit similar E vs thickness trends. respect to the bulk FCC structure.. A non-linear stress response to strain is observed, as reported by other authors [2]. The combination of both this axial contraction and the nonlinear stress/strain observed induces an orientational dependence of the E vs R curves: As thinner nanowires are studied, the Young’s modulus E deviates with respect to the bulk value Ebulk. From these simulations we have confirmed and extended previous results by other authors regarding the orientational dependence of the elastic properties in these systems. Nanowire families of different cross-sectional shapes but having the same crystallographic axial orientation exhibit similar trends; in other words, the kind of exposed facets plays a secondary role in comparison with the crystallographic orientation. We have observed a strong nanowire axial contraction of these nanowires with respect to the bulk crystal. This contraction also shows only orientation-dependent trends and compression tends to zero as thicker NWs are considered. Despite the nanowire orientation, shape or size, the atomic stress of surface atoms is in general positive, the core atoms negative and the difference between surface and core atoms is larger as the nanowire is thinner. On the contrary, the variation of the atomic stress with the strain inside the nanowire depend on the axial orientation (and therefore the “atomic Young’s moduli”). For nanowires with [100] orientation, core atoms show a larger variation of stress than the surface atoms when the strain is changed, i.e., core atoms have stronger “atomic Young’s moduli” than surface one. For the [110] orientation the situation is reversed, core atoms have a lower “atomic Young’s moduli” than the surface. In the [111] orientation we have observed a mixed situation, surface atoms show are ‘soft’ (low “atomic Young’s moduli”), second layer (from surface) atoms are the ‘hardest’, and core atoms are again ‘soft’. As a consequence of these behaviors and because the “atomic Young’s moduli” of surface atoms is the dominate term in the thin nanowires (when the number of surface atoms are larger or equal than the number of core atoms), for the [100] nanowires E<Ebulk, and for [110] and [111] orientations E>Ebulk,

This work has been partially supported by the Spanish Goverment through projects FIS2012-36113C01/C02 and CSD2010-00024 (Forces for Future) and by the Madrid Regional Government through the Programs CM-S2009/MAT1467 (NanoObjetos-CM) and CM-S2009/TIC-1476 (Microseres-CM).

References [1] S. Peláez, P. García-Mochales and P.A. Serena, Computational Materials Science 58 (2012) 1–6. [2] H. Liang, M. Upmanyu, and H. Huang, Physical Review B 71 (2005) 241403; Y. Wen, Y. Zhang and Z. Zhu, Physical Review B 76 (2007) 125423; Y. Wen, S. Wu, J. Zhang, and Z. Zhu, Solid State Communications 146 (2008) 253-257. Figures

Figure 1: Young’s modulus E of the nanowires under study. For every nanowire family, E is normalized by the bulk value Ebulk along the corresponding orientation. The corresponding geometries and crystallographic directions for each curve are indicated in the legend

Figure 2: Atomic stress σzz of the more stable configurations (minimum cohesive energy) for several geometries of Al nanowires. In general surface atoms show a positive stress and core atoms negative stress; how σzz varies inside the nanowire and with the strain depend on the nanowire geometry

Hybrid (electronic Âą x-ray) nanomicroscope (HNÉ&#x2C6;É&#x2020;Âą40) for nanotechnology. Gelever V. D. Repin D. S. Manushkin A. A. Usachev E.Ju. Moscow State Technical University for Radioengineering, Electronics and Automation (MSTU MIREA), 5 Sokolinaja gora st., 22, 105275 Moscow, Russia e-mail: gelgan@yandex.ru Hybrid (electronic Âą x-UD\ QDQRPLFURVFRSH +1É&#x2C6;É&#x2020;Âą40) [1, 2, 3] is an electron-probe device that combines electronic and x-ray microscopy (Fig. 1). It is intended for complex diagnostics and control of nanosctructured objects size of which is about few millimeters. The microscope utilize tungsten thermionic cathode operating under accelerating potential 1-40kV. HNÉ&#x2C6;É&#x2020;-40 has following modes and parameters: Ę&#x2039; 1. 2. 3. 4. 5.

Name of mode Scanning mode in secondary electrons Scanning mode in transmission electrons Scanning mode in elastically scattered electrons Projection xÂąray mode Scanning xÂąray mode

Conditions vacuum vacuum vacuum/air vacuum/air vacuum/air

Max. resolution (nm) 2-3 1-2 10 20-30 50

Main parts of the microscope are a table electron-probe unit and two supply and control units. The electron-probe unit (Fig. 2) consist of a column (system of electromagnetic focusing lenses for electron beam and electron gun), elements of vacuum system, detectors, changeable cameras and sample stages, which are made in compliance with sizes of samples and character of research. Supply units places separately from electron-probe unit that provides access to the module for easier connection to additional detectors and devices. Probe and optic microscopes, x-ray analyzers and other components can be included in microscope (Fig. 3). The x-ray analysis of the object can be made in the ordinary x-ray radiance of target and by registration of x-ray which was a result of driving thin vacuum-tight substrate (membrane) by an electron beam (the object is used as a target) as well. +1É&#x2C6;É&#x2020;-40 allows to analyse surface and examine internal structure in different modes. X-ray source make it possible to explore samples without any destruction and advance preparation in the air or in liquid phase. For realisation of limit resolution in x-ray mode an ultra-thin target substrate is used which provides micron distances, object focus (target) and high zooms. There exist several modifications of microscope. They allow to solve specific research tasks, SURGXFWLRQ FRQWURO DV ZHOO DV WUDLQLQJ VSHFLDOLVWV +1É&#x2C6;É&#x2020;-40 has simple construction, small size, low cost and maximum parameters in all modes. References [1] V. D. Gelever //Nanoindustry- Ę&#x2039; 3,6 (in Russian). [2] Gelever V. D., Manushkin A. A., Chakhlov S. V., Malyasov M. N. // Proceedings of 10th European conference on non-destructive testing Âą Part. 1 2010. Âą p. 213-215. [3] V. D. *HOHYHU 3DWHQW 58 Ę&#x2039; 5XVVLDQ 27.12.10.

Fig. 1. Scheme combining SEM and XRM. model.

Fig. 2. Electron-probe

unit

experimental

Fig. 3. Scheme combining of electron, x-ray and probe microscopes. (NP ± nanopaticle, TE ± transmission electron, SE ± secondary electron, PE ± primary electron, XD ± x-ray detector, TED ± transmission electron detector, SED ± secondary electron detector, ESED ± elastically scattered electron detector).

Analytical usefulness of the combined use of Tb4O7 nanoparticles and laccase enzyme for the determination of antioxidants in food samples Juan Godoy-Navajas, María Paz Aguilar-Caballos, Agustina Gómez-Hens Analytical Chemistry Department. Institute of Fine Chemistry and Nanochemistry. Campus of Rabanales. Annex to Marie Curie Building. University of Córdoba. 14071-Córdoba. Spain. Phone number: +34-957218645, Fax: +34-957218644 e-mail: qa1gohea@uco.es, web: http://www.uco.es/investiga/grupos/FQM-303 The analytical usefulness of terbium oxide nanoparticles (Tb4O7 NPs) for the determination of phenolic compounds in food samples in combination with the use of laccase enzyme is described for the first time. Laccases are oxidase-phenol enzymes, which are isolated from several types of plants, fungus and microorganisms, the most used variety being Trametes Versicolor. Laccase enzyme catalyzes the oxidation of phenolic compounds by reducing the dissolved oxygen present in the medium. This reduction can also be monitored by its action on 1 some chromophores, such as 2,2´-azino-bis-(3-ethylbenzothiazolin-6-sulfonic) acid (ABTS) . The use of the fluorophore 8-hydroxypyrene-3-sulfonate trisodium (HPTS), which fluorescence decreases in presence of laccase, is now reported. The observed decrease is lower in presence of antioxidant compounds, such as gallic acid, which has been used as model analyte. The areas under the kinetic curves obtained in presence of this antioxidant are directly proportional to its concentration. The presence of Tb4O7 NPs in the reaction medium gives rise to an increased reaction rate, which provides shorter analysis times, and hence, a better sample throughput. This novel assay has been developed in a 96-well microplate format and it consists of two steps: 1) Pre-incubation of HPTS together with gallic acid standards or samples for 15 min at 37 o C, and 2) the addition of a pre-mixed solution, which contains a mixture of Tb4O7 NPs and laccase. This mixture is placed immediately on the microplate reader and kinetic curves are monitored using filters with nominal excitation and emission wavelengths of 450 and 535 nm, respectively. The method shows a detection limit of 0.14 µM and dynamic range of 0.5 - 12 µM. The precision, expressed as relative standard deviation, has been assayed at two different concentrations, 0.7 and 5 µM, obtaining values between 2.5 and 6.3 %. The method has been applied to the analysis of wine and beer samples, which demonstrates its analytical usefulness. References 1 Branchi, B., Galli, C., Gentili, P., Org. Biomol. Chem., 3 (2005) 2604.

Non-Markovian effects in waveguide-mediated entanglement between qubits C. Gonzalez-Ballestero1, F.J. Garcia-Vidal1 and Esteban Moreno1 1 Departamento de F铆sica Te贸rica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Aut贸noma de Madrid, Madrid 28049, Spain carlos.ballestero@uam.es

Abstract During last years, intense efforts have been made to control and tailor the coupling between quantum emitters and the electromagnetic field. One of the areas in which this research is very promising is quantum information, where quantum entangled states of two emitters (or qubits) are the basis of quantum cryptography, quantum teleportation and other quantum operations. Short-distance entanglement is available in many optic, atomic, and molecular systems. However, for information transmission purposes, it is necessary to entangle emitters separated by a long distance. In order to achieve this goal, and also to control the field-matter interaction, waveguides arise as a very promising system. Their broader band for Purcell enhancement, the high beta factors, and the low dimensionality allow to have strong photon-qubit interaction in a similar way as cavity QED. Moreover, waveguides offer interesting possibilities such as entangling photons via evanescent coupling. Finally, the fact that photons are directly usable (in opposition to cavity systems) suggests that these systems are good candidates for the design and implementation of circuit QED devices. Recently, long distance entanglement between two qubits mediated by surface plasmon polaritons in a one-dimensional plasmonic waveguide (Fig. 1) has been reported [1]. It has been shown that, for specific distances between qubits, a collective symmetric / antisymmetric entangled configuration can be practically decoupled from the dynamics of the rest of states, thus giving rise to very small decay rates. This results in a long lifetime of the entangled state, even if the beta factor associated with the waveguide is smaller than unity. The dependence of the coupling parameters with the inter-qubit distance makes it possible to tune the degree of entanglement desired. The above mentioned calculations are based in a density matrix formalism, which is widely used in quantum optics. This method traces out the electromagnetic degrees of freedom within the Markovian approximation. In this work [2] we present a complete QED solution of the hamiltonian, which allows us to study the system outside the Markovian regime. In the real space formalism we use [3], the photonic degrees of freedom are also considered in the dynamics. This is a key feature for quantum plasmonics purposes, as intrinsically photonic properties such as nonclassical correlations could now be calculated. In our study, we obtain a new branch of quasi-localized eigenstates which plays a key role in the time evolution of the qubit populations. With this complete solution we are able to recover the Markovian results for low qubit-waveguide coupling [Fig. 2 (a) ]. Our results show, however, that Markov approximation is not valid when the qubit-waveguide coupling is increased. The onedimensional character of the system makes it to be non-Markovian in this regime, as photons undergo sucessive reflections between both qubits. In contrast to what intuition suggests, a stronger coupling between qubits and guided photonic modes decreases the role of the collective effects, as well as the entanglement properties [Fig. 2 (b)]. Our results show that the dynamics of this system evolves from collective evolution in the Markovian regime to single-qubit evolution for high waveguide-qubit coupling. By modifying either the inter-qubit separation or the waveguide-qubit coupling, we can change from one regime to another, thus controlling the evolution of the qubit states. This control of the degree of entanglement may be useful for circuit QED purposes, and also to study strong light-matter interaction phenomena. References [1] A. Gonzalez-Tudela et al., Phys. Rev. Lett. 106, 020501 (2011) [2] C. Gonzalez-Ballestero et al., arXiv:1304.6902 [quant-ph] [3] H.Zheng and H.U.Baranger Phys. Rev. Lett. 110, 113601 (2013)

Figure 1. Sketch of the system under study. Two qubits with frequency ÎŠ are placed near a waveguide, coupled to it through an energy Îł, and emitting to free space modes at a rate Î&#x201C;.

Figure 2. Time evolution of the populations of the entangled symmetric (+) and antisymmetric (-) states, and the corresponding concurrence. a) Markovian regime. b) Non-Markovian regime.

Electrochemical Study of Polypyrrole Coated Electrospun Polycaprolactone Nanofibers and Their Potential Application in Biosensors 1

Zeliha Guler , Pelin Erkoc , A. Sezai Sarac

1,2,3

Istanbul Technical University, Nanoscience and Nanoengineering, Istanbul, Maslak, 34469, Turkey. 2

Istanbul Technical University, Department of Chemistry, Istanbul, Maslak, 34469, Turkey.

Istanbul Technical University, Department of Chemistry, Polymer Science and Technology Istanbul, Maslak, 34469, Turkey. zelihaguler@gmail.com zelihaglr@gmail.com

Biosensor designs which consistent of a bio-receptor and a transducer components [1] are emerging at a significant rate since they are rapid, simple and inexpensive analytical tools for detection of certain analyte [2]. Conductive polymers (CPs), such as polypyrrole (PPy), have been extensively used as transducer in biosensors. CPs exhibit interesting and promising electrical properties such as relatively high conductivity and good environmental stability [3]. By the immobilization of biomolecules on surfaces it is possible to develop biologically functionalized materials as biosensors [4]. In this study, Pyrrole (Py) was polymerized on Polycaprolactone (PCL) nanofibers as electrochemical transducer surface were characterized via electrochemical impedance spectroscopy (EIS). PCL nanofibers were fabricated by elecrospinning technique. PPy was polymerized on electrospun PCL +

nanofibers by in-situ polymerization with Fe3 as an oxidant and Cl as a dopant. The calf thymus singlestranded DNA (ssDNA) was immobilized on the PPy coated PCL nanofibers. Surface morphologies of nanofibers were analysed by SEM (Figure 1). The structural properties of PCL, PCL-PPy and ssDNA immobilized PCL-PPy nanofibers were investigated by using an FTIR-ATR spectrophotometer (Figure 2). EIS measurements and equivalent circuit fitting were performed (Figure 3, Table 1). PPy coated PCL nanofiber mat exhibited nearly ideal capacitor feature. This is a promising structure which can be used for electrochemical DNA biosensor applications with the further optimizations. References [1] Kelley, S.O., Boon, E.M., Barton, J.K., Jackson, N.M., Hill, M.G., Nucl. Acids Res., 1999, 4830–4837. [2] V. Velusamy, K. Arshak, O. Korostynska, K. Oliwa, C. Adley, Proc. of SPIE, 2009, 7315 731504-1. [3] M. I. Rodríguez and E. C. Alocilja, IEEE Sensors Journal, 2005, 5, 4, 733. [4] J.Berganza, G. Olabarria, R. Garc´ıa, D. Verdoy, A. Rebollo, S. Arana, Biosensors and Bioelectronics, 2007, 22, 2132–2137.. Figures

Figure 1. SEM images of nanofibers. A,B,C,D show PCL nanofibers; E,F,G,H indicate PPy coated PCL electropun nanofibers. The images have 20,10,5 and 2 µm scale bars in order left to right.

Figure 2. FT-IR-ATR spectra of PCL, PCL-PPy and PCL-PPy-DNA nanofibers. The spectra presents (a) calf thymus DNA(10ÂľM) immobilized on PPy coated PCL nanofibers (b) PPy coated PCL nanofibers (c) PCL nanofibers (d) Single Stranded calf thymus DNA.

Figure 3. Equivalent circuit modeling of DNA immobilized PCL-PPy. Nyquist (a), Bode phase (b), Bode magnitude (c) and Admittance (d) plots of PCL-PPy-DNA nanofibers. Table 1. Equivalent circuit components for simulating the impedance spectra. Inset: R(Q(R)(CR)(CR)).

Rs CPE R C R C R

638.8 Ohmxcm2 2.825 10-6 Sxsecn/ cm2 2.712 109 1.821 10-5 F/cm2 1.823 105 0.02123 F/cm2 2233

Effect of etch and growth parameters on the properties of epitaxial graphene grown on 6H-SiC 1

T. Hopf , K.V. Vassilevski , E. Escobedo-Cousin , N.G. Wright , A.G. O’Neill , A.B. Horsfall , J.P. 1 2 2 Goss , G.H. Wells , M.R.C. Hunt 1

School of Electrical and Electronic Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom 2 Department of Physics, Durham University, Durham, DH1 3LE, United Kingdom toby.hopf@ncl.ac.uk

Abstract Multilayer epitaxial graphene has been grown on the Si-face of 6H-SiC on-axis commercial substrates -5 under high vacuum (< 3×10 torr) and at high temperature (up to 1900 ⁰C), utilizing the standard sublimation growth technique [1] and a modified SiC rapid thermal annealing system which allows for excellent control of heating and cooling ramp rates. A number of different growth parameters have been systematically varied in order to ascertain their effect on the formation of epitaxial graphene, and both the initial substrate etch step and the subsequent high temperature growth step were found to have a significant influence on the properties of the graphene that grew over the SiC substrates. After growth, graphene quality and uniformity across the surface were measured by Raman spectroscopy using a 514.5 nm laser with a 700 nm spot size, while the surface morphology was probed in detail using atomic force microscopy (AFM) and scanning tunneling microscopy (STM). Prior to graphene growth, the SiC substrates were first subject to an etch step to remove the surface damage which occurs during the mechanical polishing of the wafers. This step is generally performed in pure hydrogen gas [2], however in this case an Ar/H2 forming gas mixture at 5% H2 concentration was used, with the etching done at a pressure of 1000 mbar. The use of forming gas to pre-etch the SiC substrates was investigated by varying the etch parameters and observing the effect this had both on SiC surface morphology and on subsequent graphene growth. The morphology of the SiC substrate in particular was found to be highly sensitive to the etching temperature: while a 1600⁰C etch step produced uniform single atomic steps across the surface, a 1550 ⁰C etch step led to broad non-uniform terraces, and etching at 1650 ⁰C led to significant bunching of atomic steps across the SiC surface (Figure 1a-c). Etching at even higher temperatures was found to lead to step roughening, as well as to the appearance of etch pits across the SiC surface [3]. After optimization of the SiC etch step with respect to morphology, systematic studies on the effect of a variety of different growth parameters on the quality of the resultant graphene layers were performed. -1 These demonstrated that the Raman D peak at approximately 1380 cm , associated with defects in the epitaxial graphene, could be minimized either by performing growths at a higher temperature (Figure 2a) or else by growing graphene over longer time periods at a lower temperature (Figure 2b). Although both methods were effective at reducing the D peak, graphene growth at too high a temperature was found to have highly deleterious effects on the surface morphology, with the formation of a high density of etch pits resulting from growth at 1900 ⁰C (Figure 3a). This was in marked contrast to results from lower temperature growth runs, where the uniform SiC step structure formed during the etch step was found to be unaffected by subsequent graphene growth (Figure 3b). -1

In all cases, the FWHM of the 2D Raman peak was measured at between 65-75 cm , by which it can be estimated that 2-3 layers of epitaxial graphene has been consistently grown on top of the SiC substrates [4]. This was verified by Auger spectroscopy, and STM/LEED was used to confirm the presence of epitaxial graphene on the SiC surface after the growth step (Figure 3c). This growth was found to be self-limiting, with longer growth runs or higher temperatures having no further effect on the width of the 2D peak. Ultimately, an optimal combination of good surface morphology and uniform graphene growth with a small associated Raman D peak was found to be obtainable only through the use of long growth times at an intermediate (1775 ⁰C) furnace temperature. In-depth studies on the morphology of the surface using STM also revealed the presence of numerous white lines representing wrinkles or folds in the epitaxial graphene film after growth on the SiC surface (Figure 3d). These features are believed to be caused by the differing thermal expansions of graphene and SiC, with strain release of the graphene during sample cooling being mediated by the formation of wrinkles across the surface [5]. A detailed investigation of this effect as a function of the sample cooling rates after high-temperature graphene growth will be presented.

Acknowledgement. This work was supported by the Leverhulme Trust (F/00 125/AN). References [1] C. Berger et al., Science, 312 (2006) 1191. [2] N. Srivastava et al., J. Phys. D: Appl. Phys., 45 (2012) 154001. [3] J.B. Hannon and R.M. Tromp, Phys. Rev. B, 77 (2008) 241404. [4] D.S. Lee et al., Nano Lett., 8 (2008) 4320. [5] G.F. Sun et al., Nanotechnol., 20 (2009) 355701. Figures

Fig. 1. 24×24 μm atomic force microscopy images showing the sensitivity of the SiC substrate to etching temperature. Samples were all etched in Ar forming gas with a 5% H2 concentration, using the following etch parameters: (a) 1550 ⁰C for 4 min; (b) 1600 ⁰C for 4 min; (c) 1650 ⁰C for 4 min.

Fig. 2. (a) Raman spectra of epitaxial graphene on 6H-SiC as a function of the peak growth temperature; (b) Raman spectra of epitaxial graphene on 6H-SiC as a function of the growth time at peak temperature.

Fig. 3. (a) 10×10 μm atomic force microscopy image of the SiC surface after growth of graphene at 1900 ⁰C for 4 minutes; (b) 10×10 μm atomic force microscopy image of the SiC surface after growth of graphene at 1775 ⁰C for 55 minutes; (c) Atomic-resolution STM image of the epitaxial graphene layer after growth; (c, inset) LEED image confirming the presence of epitaxial graphene on the SiC surface; (d) STM image showing the wrinkling of the epitaxial graphene after growth on the SiC surface.

Preparation and Electrochemical Characterization of Glutathione Modified Gold Nanoelectrodes a, b

Radim Hrdy

a, b

, Eva Vrbova , Jana Drbohlavova , Hana Kynclova a, b Jaromir Hubalek

a, b

, Vojtech Svatos

a, b

Department of Microelectronic, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 10, 616 00 Brno, Czech Republic b Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, 616 00 Brno, Czech Republic hrdy@feec.vutbr.cz

Abstract The gold nanomaterials are used extensively in biosensors due to their biocompatibility as well as high effective surface area. Ordered arrays of gold nanostructure materials have exceptional potential to increase the sensitivity of biosensors. We demonstrated the one of low cost technique, how to prepared biosensor based on vertically aligned gold nanorods (NRs) array, which was fabricated by pulsed electrodeposition method. The advantages of sensing interfaces that contain Au NRs networks are the increased surface area for sensing, improved electrical connectivity through the Au NRs network, and chemical accessibility to the analyte through these networks compared to sensing interfaces based on ﬂat Au surfaces. The next advantage is an electrocatalysis. A biosensor is an analytical tool that fulfills two functions, [1] capturing biological targets and [2] transducing target binding events to measurable signals. One of the linkers for biomolecule binding to sensitive part of biosensor is glutathione (GSH), a very attractive biomolecule for sensors application due to Au-SH binding capability, bio-selectivity and high sensitivity to heavy metal ions. The combination of GSH and nanostructured surfaces could bring many new benefits. EIS (electrochemical impedance spectroscopy) has been employed to characterize the glutathione monolayer assembled on nanostructured gold electrodes. The EIS measurements of surfaces with various nanoparticles geometry have shown the changes of surface properties during the adsorption process of glutathione GSH. According to the simple equivalent electric network of the electrochemical interface; the EIS parameters were also obtained. The results showed that the proposed method should be used in wider application in biochemistry. The fabrication of flat gold and nanostructured electrodes, prepared by template based method, has been briefly described in recent paper [3]. The method has been modified by pulse deposition technique, which brings more benefits as homogeneity of nanowires distribution and better controlling of their growing, as it is shown on Fig.1. The using of pulse deposition prevents the collapse of continual deposited NRs. The comparison of flat and nanostructured electrode EIS spectra has also shown an interesting difference in diffusion part of spectra, Fig.2a. The GSH monolayer has been prepared by adsorption method in 0.1 M glutathione for different times. Measuring system Metrohm µAutolab III with FRA2 module supported by NOVA 1.8 software was used for the EIS of electrodes. Samples were measured in 10 ml of phosphate buffer (pH 7.5), frequency range of 1 Hz – 250 kHz and the amplitude of 10 mV. The EIS experiments were carried out in potentiostatic regime under DC zero potential related to reference electrode. It is supposed that measured biomolecules serve as electron transmitters. In the case of biomolecules higher concentration in the solution, the biomolecules completely covered the electrodes surface. The optimal time for GSH monolayers formation and characterization of the electrodes behavior after monolayer formation were determined. The point, where the electrode has been completely covered by GSH is shown in Fig.2b. In the following step, it is possible to measure only the biomolecules impedance instead of the measurement of impedance count corresponding to the electrode and biomolecules. Acknowledgment This research was supported by the project Research4Industry, the registration number CZ.1.07/2.4.00/17.0006. The described research was performed in laboratories supported by the SIX project; the registration number CZ.1.05/2.1.00/03.0072, the operational program Research and Development for Innovation.

References [1] Zhou A, Xie Q, Yao S, et al.: Journal of Colloid and Interface Science, 229 (2000), 12-20 [2] Suni I, et al.: Trends in Analytical Electrochemistry, 27 (2008), 7, 29-36 [3] Hrdy R, Kynclova H, et al.: International Journal of Electrochemical Science, 3 (2013), 429-447

Fig. 1., SEM image of electrode surface covered with pulse deposited Au NRs (a), and overgrowth nanowires deposited by continual deposition (b).

formed GSH monolayer

flat electrode

nanostructured electrode

GSH layer growing nanostructured electrode

Fig. 2., Nyquist plots of flat vs. Au NRs modified electrodes (a), EIS of GSH monolayer formation (b).

Theory of strong coupling between quantum emitters and propagating surface plasmons

Paloma A. Huidobro1, A. González-Tudela1, L. Martín-Moreno2, C. Tejedor1, F. J. García-Vidal1 1

Departamento de Fisica Teorica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autonoma de Madrid, 28049, Spain. 2 Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, E-50009, Zaragoza, Spain paloma.arroyo@uam.es Abstract Propagating surface plasmon polaritons (SPPs) are well-known to have both a subwavelength light confinement and long propagation lengths [1]. For this reason, their interaction with quantum emitters (QEs) has attracted great interest recently. The emergence of Strong Coupling (SC) when an ensemble of QE, such as organic molecules and quantum dots, is placed in the vicinity of a metal surface has been experimentally demonstrated [2-4]. In this contribution [5] we present the theoretical foundation of the phenomenon of SC between QEs and propagating SPPs in two-dimensional metal surfaces (see Fig. 1). For that purpose, we develop an ab-initio quantum framework that accounts for the coherent coupling between emitters and surface plasmons and incorporates the presence of dissipation and dephasing self-consistently through an open quantum system formalism. Our formalism is able to reveal the key physical mechanisms that explain the reported phenomenology in the case of disordered ensembles of emitters, and determine the physical parameters that optimize the strong coupling. Remarkably, the development of this general quantum framework to describe the SC between SPPs and QE enables us to address the fundamental nature (classical versus quantum) of this phenomenon by analyzing the conditions in which photon antibunching could be observed (see Fig. 2). References [1] T. W. Ebbesen et al, Physics Today 5, 44 (2008) [2] J. Bellessa et al, Phys. Rev. Lett. 93, 036404 (2004) [3] T. K. Hakala et al, Phys. Rev. Lett. 103, 053602 (2009) [4] P. Vasa et al, Phys. Rev. Lett. 101, 116801 (2008) [5] A. González-Tudela, P. A. Huidobro, L. Martín-Moreno, C. Tejedor, F. J. García-Vidal, Phys. Rev. Lett. 110, 126801 (2013)

Figures

Figure 1. (a) Sketch of the system: N quantum emitters embedded in a dielectric host that is placed on top of a spacer layer and a metal film. (b) Coupling constant between a single emitter and the surface plasmons propagating along the metal surface.

Figure 2. Antibunching. (a) Contour plot of g(2)(0) as a function of the nonlinearity |UD|/gN and detuning

for the coherently pumped configuration, with system parameters: s =10 nm, W =10 nm, and n = 106 m3, which yields gN = 50 meV. The color code is 0 blue, 1 white, 2 red. (b) Horizontal cuts of (a) at two fixed nonlinear parameters: |UD| = 0.005gN (dashed red) and 0.025gN (solid black). Inset: g(2)(Ď&#x201E;) for a system with |UD| = 0.025gN (solid black) and |UD| = 0 for both incoherent pumping (dashed green) and coherent excitation (dotted blue).

Comparison between optical properties of oxidized and non-oxidized MoS2 monolayer Maya Isarov, Jenya Tilchin, Georgy I. Maikov, Efrat Lifshitz Technion-Israel Institute of Technology, Haifa, Israel mayai@tx.technion.ac.il Arend van der Zande Columbia University, New York, USA MoS2 is a semiconductor material with hexagonal lattice structure. Bulk MoS2 has an indirect band gap while a single monolayer behaves like a direct semiconductor. In comparison with graphene thickness of one atom, the MoS2 monolayer has thickness of three atoms, giving the monolayer more stiffness. MoS2 monolayer features make it a good candidate to serve as a component in optical triggered switches. [1] In this work MoS2 monolayers were grown on top of SiO2 substrate (with courtesy to Dr. van der Zande from Columbia University for the preparation of the samples). The properties of the samples were examined on a resolution of a single monolayer utilizing combined method, comprised of atomic force microscopy (AFM) and confocal spectroscopy (photograph of the set-up is given in Fig.1). This combination eliminates average effects found in a measure of an ensemble and uncover the properties of individual monolayers. The emission spectra were recorded at 4 K under cw and picosecond pulsed non-resonant excitation with various laser powers and presence of magnetic fields of various strengths, as well as at different polarized detection filtering. We had obtained two different types of behavior of the monolayers under light exposure (Fig.2). The first one possesses mainly a strong emission band with typical peak energy at ~1.9 eV and a lifetime 300-500 psec (Fig.2 right inset).The second type has an additional low energy shoulder at 1.75-1.85 eV, with a bi-exponential lifetime, Ď&#x201E;=17 and 175 nsec, as shown in Fig.2 left inset. The emission shoulder can be correlated with a bound exciton formation on surface defects, while the absence of the shoulder could refer to non-oxidized surface [3], where oxygen substitutes the sulfur vacancies. Furthermore, the main band is shifted up to 21 meV to a new position under illumination with time (see dependent plot in Fig.3). This shift can be related to a transfer of a neutral exciton to a charged exciton after certain irradiation exposure. Recently, Mak et al.[2] had shown the activation of this charged emission channel by applying a gate voltage on a monolayer. By examining five different layers we obtained that high excitation power reduces the time for layer charging, as shown in Fig.3 right inset. A typical exposure time evolution of these two states throughout 600 sec is presented in Fig.3 middle inset. At 120 sec there is equal intensity exchange between the two states. The shift to the charged state is irreversible. After 18 hours at dark, the spectrum exhibits slight red shift and broadening, as shown in Fig.3 left inset. Since the charging effect possesses irreversibility, we preliminary exposed the layer to intense laser and then recorded the power dependent emission. All of the monolayers showed a sub-linear dependence, suggesting the existence of different emission channels. Also, they exhibit an additional high energy band, blue shifted by 155 meV above the main band (Fig.2). This band is in good agreement with the spin-orbit interaction splitting of the valence band edge. The polarization measurements at zero magnetic field reveal a slight linear and circular polarized components of the main emission peak. Fig.4.a represents emission intensity dependence under circular polarization detection. The broad structure of the emission line suggests that the exciton recombines throughout a number of the acoustic and optic phonon channels. This admixture of the emission channels breaks a pure polarization identity of the recombination channel. The polarization measurements at 8 T reveal energy difference of ~2.5 meV between circular polarizations (Fig.4.b). Future measurements and investigation shall be done for better understanding of MoS2 monolayers features. References: [1] K. F. Mak et al., Physical Review Letters 105, 136805, 2010 [2] K. F. Mak et al., Nature Materials 12, 207, 2013 [3] G. Plechinger et al., Phys Status Solidi RRL 6 (3), 126, 2012

1.9217 eV

1.9428 eV

PL after 18 hours 1.8 2 2.2 Energy (eV)

100

0 sec 600 sec

1.8

200

T im e (sec)

cps

1000 500

2 2.2 Energy (eV)

300 Time (sec)

0.1 0.6 1.1 Laser power (mW)

400

500

Figure 3: Intensity dependence on exposure time of oxidized monolayer, measured at two different energies (see legend).Left inset: PL vs. PL after 18 hours at dark of the same monolayer. Middle inset: PL recorded at 0 and 600 sec under irradiation. Right inset:Interception time between neutral and charged states of 5 different monolayers at various laser powers. Figure 1: Combined AFM-Confocal Microscope system.

non oxidized oxidized

σ+

150

1 250 500 Time (ns)

750

100

1 2 Time (ns)

1.7

1.8

1.9 2 Energy (eV)

2.1

Figure 2: PL spectra of oxidized (red) and non-oxidized (blue) monolayers.Right inset: PL-decay curve of the main band at ~ 1.9 eV. Left inset: Low energy band between 1.75 – 1.85 eV.

1.8

b 1

1.9 2 Energy (eV)

2.1

σ+ σ-

Norm. Intensity

cps

Normalized Intensity

~2.5 meV

1.9 1.95 Energy (eV)

1.85

1.95 Energy (eV)

2.05

Figure 4: Circular polarized emission: a. At zero magnetic field. b. At 8 T. Inset: Energy difference 2 between s+ , s-.

Integration of gold nanoparticles in photonic crystals: effect of the interplay between plasmonic and optical cavity resonances 1

Alberto Jiménez-Solano , Carmen López-López , Olalla Sánchez-Sobrado , José Miguel Luque , 1 2 2 2 Mauricio E. Calvo , Cristina Fernández-López , Ana Sánchez-Iglesias , Luis M. Liz-Marzán and 2 Hernán Míguez 1

Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones CientíficasUniversidad de Sevilla, C/ Américo Vespucio 49, 41092 Sevilla, Spain 2 Departamento de Química Física, Universidad de Vigo, 36310 Vigo, Spain alberto.jimenez@csic.es

Abstract Herein we show experimental examples of localized photon modes in periodical multilayer structures. [1,2] These experiments show the control of the spectral modification of the optical absorption of onedimensional photonic crystal based resonators containing different types of gold nanoparticles. This control was achieved through the changes in the photonic environment of the gold nanoparticles by means of the interplay between planar optical cavity modes and localized surface plamons. Spin-casting of metal oxide nanoparticle suspensions was used to build multilayered photonic structures [3] that host (silica-coated) gold nanorods and spheres (Figure 1). Strong reinforcement and depletion of the absorptance was observed at designed wavelength ranges, thus proving that our method provides a reliable means to modify the optical absorption originated at plasmonic resonances of particles of arbitrary shape and within a wide range of sizes. Results are explained in terms of the calculated spatial distribution of the electric field intensity within the configurations under analysis.[4] References [1] Sánchez-Sobrado, O., Lozano, G., Calvo, M.E., Sánchez-Iglesias, A., Liz-Marzán, L.M. and Míguez, H. Adv. Mater. 23 (2011) 2108-2112. [2] Jiménez-Solano, A., López-López, C., Sánchez-Sobrado, O., Luque, J.M., Calvo, M.E., FernándezLópez, C., Sánchez-Iglesias, A., Liz-Marzán, L.M. and Míguez, H. Langmuir 28 (2012) 9161-9167. [3] Colodrero, S., Ocaña, M. and Míguez, H. Langmuir 24 (2008) 4430-4434. [4] Anaya, M., Calvo, M.E., Luque-Raigón, J.M. And Míguez, H. J. Am. Chem. Soc. 135, (2013) 78037806.

Figures

Figure 1. Top: TEM images of Au@SiO2 nanospheres (a) and rods (b). Bottom: SEM backscattered electrons images of cross sections of optical resonators hosting Au@SiO 2 nanospheres (c) and rods (d).

Formation of gallium micro- and nano-spheres by ultrasonic cavitation and entrapment of organic substances within them. Vijay Bhooshan Kumar , Yuri Koltypin , Aharon Gedanken DQG =HÂśHY 3RUDW 1

2,3*

(1) Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel. (2) Division of Chemistry, Nuclear Research Center-1HJHY %HÂśHU-Sheva 84190, Israel and (3) Institute of applied Research, Ben-*XULRQ 8QLYHUVLW\ %HÂśHU-Sheva 84105 Israel. *Corresponding authors: koltypy@mail.biu.ac.il, poratze@post.bgu.ac.il o

Pure gallium has a low melting point (29.8 C) and can be melted in warm water or in organic liquids, thus forming two immiscible liquid phases. Irradiation of this system with ultrasonic energy causes dispersion of the molten gallium into microscopic spheres by the process of ultrasonic cavitation. The resultant spheres were found to be in the size range of 0.2-5Âľm and they do not re-coalesce after the irradiation is ceased, although the ambient temperature is well above the m.p. of gallium. It was found that spheres which were formed in water are covered with crystallites of GaO(OH) (Fig. 1), whereas those formed in organic liquids (hexane and ndodecane) are smooth, without such crystallites. However, Raman spectroscopy revealed that in organic liquids the spheres are coated with a carbon film. The GaO(OH) crystallites or the carbon film may act as the factor that prevents the re-coalescence of the spheres. When this procedure was performed in aqueous solutions of various organic materials, such as 1, 10 phemamthroline, rather than in pure water, simultaneous formation of gallium microspheres and entrapment of some of the substrate occurred. This was evidenced by lower intensity of the absorption spectrum of the substrate after the sonication and by slow leaching of the substrate during prolonged immersion of the spheres in pure water. The leaching experiments were followed by occasional sampling of the water and recording the UV-vis spetra. It showed slow growing of the absorption curves during a period of one month (Fig. 2). We assume that the entrapped molecules are located within voids in the gallium spheres, which are partly hollow.

References 1) Ultrasonic Cavitation of Molten Gallium: 1. Formation of micro- and nano-spheres; V. B. Kumar, G. Kimmel, A. Gedanken and Z. Porat, to be published. 2) Ultrasonic Cavitation of Molten Gallium in Water: 2. Entrapment of Organic Molecules in Gallium Microspheres; V. B. Kumar, Y. Koltypin, A. Gedanken and Z. Porat, to be published.

Fig. 1: SEM images of two samples, obtained after 3 min. sonication: A) A cluster of Ga spheres in water. The crystallites were identified as GaO(OH). B) A cluster of Ga spheres in dodecane.

Fig. 2: UV-vis. spetra of 1, 10 phenanthroline after various leaching times. The dilution factor for all the curves is 40.

Transfer and weighing of graphene flakes by using a nanowire mass sensor 1

2,3

Jelena Kosmaca , Jana Andzane , Justin D. Holmes , Donats Erts

Institute of Chemical Physics, University of Latvia, Raina blvd. 19, Riga, LV-1586, Latvia Materials Chemistry & Analysis Group, Department of Chemistry and the Tyndall National Institute, University College Cork, Ireland 3 Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland jelena.kosmaca@lu.lv 2

Abstract This work demonstrates an experimental method for the transfer and characterization of individual graphene flakes in situ. The great advantage of this method is preventing of environmental impact during the preparation of samples for future experiments. The experimental setup includes 13D SmarAct nanomanipulation system staged inside a Hitachi 4800 scanning electron microscope (SEM). The nanomanipulation system SmarAct preforms precise moving of its actuators with possible step size of 100nm. The scanning electron microscope enables the visualization of the experiment. The externally connected signal generator AGILENT N9310A operates in the output frequency range of 9 kHz-3 GHz with resolution of 0.1 Hz. Nanowires turned out to be suitable for shaping nanoelectromechanical mass sensor, because of their flexibility and high resonant frequencies. Ge nanowires, due to easy synthesis, monocrystalline structure and high Young’s modulus already have been applied in nanoelectromechanical switches [1]. A germanium nanowire is integrated into the nanomanipulation system as an active element (Fig. 1a, top image). Germanium nanowires are glued onto sharp electrochemically etched Au tips with conductive epoxy. To prevent oxidation of Ge nanowires, they are etched with Ar ions for 120 s using etching/coating equipment Gatan PECS 682. The self-resonance frequency of the nanowire is premeasured by applying AC field sweep to the nanowire and observing the nanowire’s behavior in SEM. This frequency depends on nanowire’s shape, mass and Young’s modulus. When the frequency of AC field fits nanowire’s self-resonance, rapid increase in nanowire’s oscillation amplitude is observed in SEM images (Fig. 1a, bottom image). Exact resonant frequency and resonator quality factor are determined from the nanowire`s deflection amplitude distribution. The resonant frequencies of the unloaded nanowires are in the range of 100 kHz, typical quality factors are from 100 up to 500. The Young’s modulus of Ge nanowires, calculated from resonant frequencies turned out to be about 70120GPa that is close to the Young’s modulus for bulk material [2]. After the self-resonance frequency of the nanowire is determined, the nanowire is used for graphene flake characterization and transferring to a substrate. Graphene samples are produced by splitting few layer thick flakes from the surface of highly oriented pyrolytic graphite. The transfer of a graphene flake is based on balancing of the adhesion interaction between the surfaces involved in the process. Due to the high adhesion between the germanium nanowire and graphitic structures, partially detached graphene flake can be picked up from the graphite surface by the free end 2 of a single-clamped nanowire (Figure 1b,c). The free surface energy of germanium (1.5 J/m [3]) is 2 higher than that of graphite (0.1-0.2 J/m [4]). Therefore a graphene flake whose contact area with the graphite surface has been decreased might adhere to germanium nanowire on a single position and stay there. The nanowire-graphene contact area relates to the nanowire thickness. In comparison, for 2 graphene flake with surface area of 1um , placed onto the end of the nanowire with radius of 50nm, the contact area is less than 1% of flake’s surface area. Loading the nanowire with graphene sample causes its resonant frequency decrease. The mass of the loading graphene flake can be calculated from the resonant frequency shift between the not loaded and loaded nanowire as following [5]: , where m0 is initial mass of nanowire, β=1.875 is an appropriate constant for the first harmonic frequency equation, f0 and f are the resonant frequencies for the not loaded and loaded nanowire. When the mass of the flake is known, the number of graphene layers in it can be calculated as following: , -6 2 where A is the surface area of the flake, ρ=0.76·10 kg/m is the graphene mass density. Shape of the flake is determined from SEM pictures (Figure 1c,d).

After the weighing procedure the graphene flake with determined mass and number of layers is transferred to the desired position on the substrate (Figure 1d).The flake transfer from the nanowire to the substrate is performed by varying contact areas and contacting materials, thus balancing adhesion interaction. Other factors that facilitate the manipulations with graphene flakes are also investigated. The nanowire mass sensor operation affecting factors are explored and discussed in this work. Presented controlled characterization transfer of graphene allows the fabrication of nanodevice prototypes under not changing laboratory conditions. This minimizes the chance of change of sample properties due to the environmental influence. The next step of our research is to realize controlled nanowire-based transport of a single layer graphene samples.

References [1] J.Andzane,, N.Petkov, A.Livshits., J.Boland, J.D.Holmes, D.Erts, Nanoletters, 9(5) (2009) 1824-1829 [2] E. Rosenberg, Reviews in Environmental Science and Biotechnology, 8(1) (2009) 29-57 [3] A.A.Stekolnikov, J.Furthmuller, F.Bechstedt, Physical Review B, 65 (2002) 115318 [4] N.Ooi , A.Rairkar, J.B.Adams, Carbon , 44 (2006) 231â&#x20AC;&#x201C;242 [5] J.Zhoua, C.Shi Laoa, P.Gaoa, W.Maia, W.L.Hughesa, S.Zhi Dengb, N.Sheng Xub, Z.Lin Wang, Solid State Communications, 139 (2006) 222-226

Figures

Figure 1: a) a single-clamped germanium nanowire (top image) and the nanowire at resonant frequency (bottom image); b) graphene flake in contact with the nanowire; c) graphene flake picked up by the end of the nanowire; d) transfer of the graphene flake to the Si substrate.

Application of a sol-gel method for functionalization of textile materials Dorota Kowalczyk, Stefan Brzeziński Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, Brzezinska 5/15, 92-103 Lodz, Poland dkowalczyk@iw.lodz.pl

Abstract Application of a silica sol containing functional nanoparticles allows to obtain thin layers, that after their deposition on textiles impart to them different performance properties. The cotton-polyester blend woven fabrics were modified with functional nanoparticles. As functional nanoparticles metallic silver and copper (Ag/Cu), TiO 2 and ZnO were used. The bonding agent for fixing functional particles with the surface of textiles was silica sol obtained on the basis of (3glicydeoxypropyl)trimethoxysilane, by the “sol-gel” method. Depending on the type of functional particles used, the cotton-polyester blend woven fabrics were characterized by very good bioactive properties and photocatalytic activity. The bioactive properties of textiles after deposition of silica sol modified with Ag/Cu nanoparticles by quantitative method were obtained. We obtained a reduction in bacteria and fungi in the range of 89% 99%. The photocatalytic activity of textiles after deposition of silica sol modified with TiO 2 or ZnO nanoparticles was determined by colorimetric method. In this method, the ability of the modified textiles to the degradation of dye deposited on the textile surface under UV radiation (302 nm) was investigated. The best effects of photocatalytic activity for textiles after deposition of silica sol containing TiO 2 in the anatase form were obtained.

Acknowledgements The study has been carried out within the Key Project – POIG.01.03.01-00-004/08 Functional nano- and micro textile materials - NANOMITEX co-financed by the European Union with the financial resources of the European Regional Development Fund and the National Centre for Research and Development within the framework of the Innovative Economy Operational Programme, 2007-2013, Priority 1. Research and development of modern technologies, Activity 1.3. Supporting R&D projects for enterprises undertaken by science establishments, Subactivity 1.3.1. Development projects.

Functionalization of textile materials with bioactive layered silicate Dorota Kowalczyk, Irena Kamińska Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, Brzezinska 5/15, 92-103 Lodz, Poland dkowalczyk@iw.lodz.pl Abstract The aim of the study was to develop modified layered silicate with bioactive particles, and then its application to the textile materials. As bioactive particles the compounds of copper (CuSO4 or Cu2O) were used. The modification of layered silicate was carried out by ion exchange in a two-step process. Changes in the structure of modified layered silicate were characterized using wide-angle Xray scattering (WAXS) and Fourier transform infrared spectroscopy (FTIR). The increase of 0.3 –5.2 Å in the interlayer distance of modified silicate was observed. This increase in the interlayer spacing indicates the intercalation of using bioactive particles into the structure of layered silicate. This intercalation occurs mainly by ion exchange, what was confirmed by elemental analysis (sodium, calcium and copper) layered silicate before and after modification carried out using energy-dispersive X-ray spectroscopy (EDX). The modified layered silicate was deposited on the polyester woven fabric by the padding method. After deposition of layered silicate containing copper on the surface of fabric, the textile material was subjected to test of bioactive properties by quantitative method. In depend on the type of functional particles used, the polyester woven fabric was characterized by bacteriostatic or bactericidal properties.

Acknowledgements The study has been carried out within the Key Project – POIG.01.03.01-00-004/08 Functional nanoand micro textile materials - NANOMITEX co-financed by the European Union with the financial resources of the European Regional Development Fund and the National Centre for Research and Development within the framework of the Innovative Economy Operational Programme, 2007-2013, Priority 1. Research and development of modern technologies, Activity 1.3. Supporting R&D projects for enterprises undertaken by science establishments, Subactivity 1.3.1. Development projects. The work was also supported by the Project WND-RPLD.03.01.00-00-001/09 and the project within statutory activities BZT 01 22.

Crystallography of -, -, and ε-iron phases and iron carbides, formed inside carbon nanotubes. HRTEM studies. B.A.Kulnitskiy, V.D.Blank, I.A.Perezhogin, Yu.S.Buranova Technological Institute for Superhard and Novel Carbon Materials (TISNCM), 7a Centralnaya Street, 142190, Troitsk, Moscow region, Russia. boris@ntcstm.troitsk.ru Carbon nanotube [1] can serve not only as a reaction chamber, but also as a container to store and preserve the structures unstable under normal conditions. In this study, by means of the catalytic growth in high isostatic pressure apparatus with varying the gas mixture composition, pressure and temperature, we obtained the carbon nanotubes inside of which we could identify some particles containing the -, -, and ε -iron phases, as well as three different iron carbides: Fe3C, Fe5C2, and Fe7C3. JEM-2010 high-resolution transmission electron microscope with the EDS and EELS techniques and JSM-7600F scanning electron microscope have been used. The present study aims to investigate the following questions: orientation relationships between -, - and ε -phases of iron and iron carbides, peculiarities of carbide formation inside carbon nanotubes, distinguishing characteristics of mutual transformations of carbides, reasons for formation of different carbon nanoconstructions. The formation of high temperature -phase of iron and high pressure -phase of iron indicates the presence of high pressure and high temperature conditions during the nanotube growth. The closed graphene shells of the nanotube represent themselves a nanochamber which prevents -- and - iron particles inside it from transformation to -iron after pressure unload and cooling. Different ways of iron – cementite (Fe3C) transformation were considered earlier [2-3]. Authors based their conclusions on parallelism of (001) cementite plane and (112) -carbide plane. As we know, there were no experimental evidences of orientation relationships between ε -Fe and cementite up to now. We have found the parallelism of (001) of cementite and (100) of Hagg’ s carbide (Fe5C2). Thus, (100) of Hagg’ s carbide is parallel to (112) of -iron. Also it is important to remark that (100) of Fe5C2 and (112) in bcc () iron are twinning planes, and the distribution of Fe atoms in these planes is favourable for the phase transformations. It was found that several atomic layers of cementite (Fe3C) are located inside the layers of Fe5C2. Planes (001) of cementite and (200) of Fe5C2 appear to be parallel. Always parallelism of corresponding planes of Fe5C2 and cementite is observed whether there is a cementite between Fe5C2 or otherwise. So, we can present following orientation relationships between all phases, found in our study: (131)γ II (2-12)ε II (112)α II (001)Fe3C II (100) Fe5C2 It is known that during the nanotube growth carbon atoms are catalytically decomposed on the catalysts surface thus building the nanotube walls, and along with this resulting in the incorporation of carbon atoms into the catalysts and formation of carbides. Often transformation of carbides to one another takes place in these cases. At high temperatures cementite decomposes into carbon and iron. It was shown by TEM analysis, that the twinning plane is (100) Fe5C2. This plane corresponds to {211} in bcc-lattice of -Fe, and this means, that in a process of saturation of -Fe with carbon and formation of

carbides the twinning plane is inherited in all the new originated carbides. Cementite develops through the intermediate phase of -iron (-Fe-FeFe3C). Consequently, one can suppose, that twinning occurs in particle with hexagonal lattice before it turns into cementite, either twinning occurs in cementite before it turns into Hagg’ s carbide. Both carbides appear in a process of nanofiber growth in the same temperature range. Hägg carbide (Fe5C2) is formed on the cementite surface, but both carbides decomposed during metal dusting. The Gibbs energy of formation Δ G for Fe5C2 was determined at 500°C. This result combined with thermodynamic properties at other temperatures taken from literature strongly supports the existence of the equilibrium of three phases: α -Fe+Fe3C+Fe5C2 at about 350°C in the binary Fe-C system. By analogy with mechanical twinning, which is the result of the mechanical stress, the new term “ chemical twinning”

was introduced. Processes, taking place in the catalyst particle in our work can

be explained also by the “ chemical twinning” , i.e., slight deviations from stehiometry, which can be achieved by the formation of thin layers. We believe, that the twinning is the result of deformation of metal particle and is caused by the action of surrounding graphene shell. The deformation leads to the twinning of not only metal catalyst particles, but also to the twinning of carbides, which mechanical characteristics are exceeding corresponding characteristics of metal. It is known, that elastic modulus of carbon nanotube walls may achieve value of 1 TPa. Strength of nanotube layers and its capability of maintaining big loads can explain existence of observed particles of ε -iron. As it is known, -iron transforms into -iron after cooling. This transformation is accompanied by the volume change of 9%. Thanks to high elastic modulus (1 TPa) of carbon nanotube, particles of -iron, being in close contact with nanotube walls, do not transform into -iron. The mechanism of twinning is connected with deformation of elementary crystal cell, leading to the change of orientation of part of the crystal relatively to the acting forces. Reoriented part of crystal suffers twin shift relatively to the other part of crystal. Value of this shift is determined by the symmetry of crystal lattice. Under real conditions, development of deformation occurs by the way of nucleation and propagation of interstitials of twinned component in original crystal. It was shown that for nanocrystals of small size (of the order of 10 nm) the deformation is realized through the twinning, whereas for crystals of bigger size key role belongs to the motion of dislocations. Carbon nanotubes, obtained on iron catalyst have been studied by the HRTEM methods. It has been established, that in growth process the lattice of catalyst particle of bcc-iron transforms into - or ε - phases or into the following carbides: Fe3C, Fe5C2 or Fe7C3. It has been shown that the inner parts of nanotubes suffer great pressure. Owing to the big values of internal pressure, nanotube can be considered as a nanoscale high pressure chamber. This is confirmed by the deformation twins in bcciron and in Hagg’ s carbide, and also by the presence of fcc- and hcp-iron particles, closed in nanotube, which can exist only at high values of pressure and temperature. References 1. [1] Iijima S., Nature, 353 (1991), 56-8. 2. [2] N.Petch, Acta Crystall., 96 (1953), 10. 3. [3] W.Pitsch, ActaMetall., 10(1962), 79.

Self pulsation behavior of a ring resonator based on nonlinear plasmonic waveguides Roxana Tomescu, Mihai Kusko and Cristian Kusko * Institute of Microtechnology, Bucharest, Romania *

corresponding author: cristian.kusko@imt.ro

In the last years, nonlinear plasmonic waveguides have been intensively investigated both numerically and theoretically mainly due to the high confinement degree of the propagating electromagnetic field as well as their interesting modal properties. Numerically it has been shown by Davoyan et al. that MDM waveguides presenting Kerr nonlinearity possess symmetry breaking bifurcation points leading to a power dependent complex modal structure [1, 2]. Also, in the case of small Kerr nonlinearities, the dispersion of MDM waveguides has been determined to quadratures for cases when the fundamental mode is symmetric and antisymmetric, respectively [3]. It has also been shown numerically, that the modification of the modal structure will lead to the power switching in nonlinear directional couplers [4]. Here we demonstrate theoretically and numerically, using FDTD algorithm, the possibility to employ plasmonic nonlinear waveguides for microring resonators, systems which exhibits self â&#x20AC;&#x201C; pulsation behavior. Essentially, the system consists in a nonlinear MDM waveguide with geometric and material parameters chosen such that for wavelengths below 500 nm, this waveguide presents an antisymmetric, backward propagating slow mode. The nature of the slow modes character of this waveguide is structural [6] such that an enhancement of nonlinearities occurs, and high phase sensitivity can be attained for lower values of electromagnetic fields. This waveguide is coupled counter â&#x20AC;&#x201C; directionally with a feedback loop consisting in an MDM waveguide supporting symmetric fast modes as it is shown in Fig 1.

Fig. 1 The schematic diagram of a the proposed plasmonic microring resonator showing self-pulsation. We have investigated the temporal behavior of the field in these systems for various geometrical and material parameters, and we show that the self â&#x20AC;&#x201C; pulsating behavior can be attained for low values of the electromagnetic fields. The time scale of the pulses generated by the investigated self-pulsating microring resonators are of the order of hundreds of femtoseconds. Moreover, due to the fact that the plasmonic waveguides operating in the slow mode regime present a high sensitivity of the group velocity with respect to the wavelength, a broad tunability of these can be achieved. The selfpulsating systems presented in this work can have applications in sub-picoseconds optical clocks [7].

References [1] A. R. Davoyan, I. V. Shadrivov, and Y. S. Kivshar, Opt. Express 16, 21209 (2008). [2] A. R. Davoyan, I. V. Shadrivov, and Y.S. Kivshar, Opt. Letters 36, 930 (2011). [3] I. D. Rukhlenko, A. Pannipitiya, and M. Premaratne, Opt. Lett. 36, 3374, 2011 [4] J. Salgueiro and Y. Kivshar, Appl. Phys. Lett. 97, 081106 (2010). [5] J. Y. Gao , L. M Narducci, L. S. Schulman, M. Squicciarini, and J. M. Yuan, Phys. Rev A 28, 2910 (1983) [6] Robert W. Boyd, J. Opt. Soc. Am. B 28, A38, (2011) [7] T. Papakyriakopoulos, K. Vlachos, A. Hatziefremidis, and H. Avramopoulos, Opt. Lett. 24, 717 (1999).

Finding the appropriate substrate for biosensors by monitoring the biomolecular recognition reactions using electrochemical impedance spectroscopy

Mihaela Kusko, Monica Simion, Adina Bragaru, Iuliana Mihalache, Razvan Pascu National Institute for Research and Development in Microtechnologies (IMT - Bucharest), Erou Iancu Nicolae Street, 32B, 72996 Bucharest, Romania mihaela.kusko@imt.ro

Abstract The electrochemical impedance spectroscopy (EIS) based detection transduces changes in interfacial properties between the electrode and the electrolyte induced by different molecules’ attachment (immobilization) on surface. This technique offers information not only about the surface modification, but it has been used to monitor the DNA hybridization, conformational changes, or damages [1]. If the other detection schemes require the labelling of the target DNA with a fluorophore, the EIS detection is a label-free tool and, thus, possesses advantages of low cost, simplicity, and ease of miniaturization [2]. Taking into account the already demonstrated optical and electrical properties of porous silicon (PS), as well as its biocompatibility, we investigated the potential of this material to be used for electrochemical based biodetection. Tuning the electrochemical process parameters, different types of PS layers have been fabricated, with pores of few nanometers (nanoSi), tens of nanometers (mesoSi) or even microns (macroSi). Since immobilization of a biomolecule on a substrate requires the presence of chemical active groups, a preliminary surface modification process by 1% APTES (3aminopropyltriethoxysilane) silanization has been followed. Thus, starting with the surface functionalization stage, each of the biomolecular recognition reaction steps for biotin-streptavidin couples have been monitored by impedance spectroscopy. The EIS spectra were recorded using PARSTAT 2273 potentiostat, the experiments being performed by applying a 10 mV rms AC amplitude at open circuit potential and frequency scanned from 100 kHz to 100 mHz. Moreover, capacitance—voltage (C-V) measurements were performed to study the hybrid structure interfaces obtained by successive immobilization / hybridization processes. 10 mM PBS in 0.1 M KCl with / without redox species (2 mM K4Fe(CN)6) was the electrolyte solution which allow us to study both faradaic and non-faradaic processes taking place at interfaces. First of all, the capacitance gain of porous structures versus the reference polished silicon ones was clearly observed, confirming the previous results [3], where a 70-fold gain up was obtained at low frequencies, due to their extended active area, which allows the scaling down of a further capacitive sensor using PS. The figure 1 (a) shows the Nyquist plotted impedance results after the successive biomolecular interactions, obtained when the nanoSi (PS 1) substrate was used. New semicircles, with larger diameters, can be identified when additional molecular coating layers are present, implying a high electron-transfer resistance, consistent with the proposed electrical circuit model. Moreover, the capacitance-voltage measurements allowed us to find the necessary time for hybridization process, and the figure 1 (b) shows the Mott-Schottky curves obtained, where is clearly revealed that the first time used hybridization was not sufficient.

References

[1] J.-Y. Park, S.-M. Park, DNA Hybridization Sensors Based on Electrochemical Impedance Spectroscopy as a Detection Tool, Sensors 9 (2009) 9513-9532 [2] J.S. Daniel, N. Pourmand, Label-Free Impedance Biosensors: Opportunities and Challenges, Electroanalysis 19 (2007) 1239–1257; [3] M. Simion, M. Kusko, I. Mihalache, A. Bragaru, Dual Detection Biosensor Based on Porous Silicon Substrate, Mater. Sci. Eng. B (2013) available online http://dx.doi.org/10.1016/j.mseb.2013.03.003;

Figures 120 15

PS1 APT - PS1 B - APT - PS1 S (t1) - B - APT - PS1 S (t2) - B - APT - PS1

8.0x10 100

(b)

(a) 15

6.0x10

-2

1/C (F )

PS1 APT - PS1 B - APT - PS1 S - B - APT - PS1

Zimg(k )

4.0x10

2.0x10 20

0.0 0

100

120

140

160

-0.8

Zre(k )

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Potential (V, vs Ag/AgCl)

Figure 1: Nyquist plots (ZImg vs ZRe) – (a) – and capacitance-voltage plots – (b) - of nanoSi (PS1) substrate subjected to successive biomolecule interactions:  surface silanization (APT – PS1);  immobilization of the capture molecule - biotin (B – APT – PS1);  hybridization with biological sample containing analyte of interest – streptavidin (S – B – APT – PS1).

Synthesis and characterization of CVD-grown graphene on copper: influence of the synthesis conditions María del Prado Lavín López, Amaya Romero Izquierdo, Jose Luis Valverde Palomino Universidad de Castilla la Mancha, Avenida Camilo José Cela Nº12, Ciudad Real, Spain prado.lavin@gmail.com Abstract Graphene, an extraordinary two dimensional carbon material with a honeycomb structure, has been the focus of many researches due to its characteristics and its extraordinary mechanical, electronic and optical properties. It can be synthesized by a variety of methods such as discharge, epitaxial growth on SiC, unzipping carbon nanotubes, reduction of CO, chemical conversion, self assembly of surfactant and Chemical Vapor Deposition (CVD)[1]. Among them, CVD method has been shown to produce large-area and high quality graphene [2]. In CVD, Ni and Cu are normally used as substrates although other transition metals are also used, but less frequently[3]. Raman spectroscopy has been shown to be the most potential method for non-destructive and quick structural and electronic characterization of graphene and graphite materials[4]. In the present work, different studies have been performed with the goal of optimizing CVD synthesis of graphene on copper. In order to achieve that objective, the influence of different synthesis conditions such as temperature (900-1050 ºC), reaction time (5-45 min), CH4/H2 ratio (3%-45%) and total flow rate of gases involved in the reaction (40-140 ml/min) have been studied. Raman spectroscopy was used to characterize the obtained products. Influence of the reaction time at different synthesis temperatures. Table 1 shows the most important characterization parameters obtained with RAMAN spectroscopy for the best reaction temperature (1050ºC) and the influence of different temperatures at the same reaction time. In general, ID/IG ratio (related with the amount of defects in the sample) tended to increase and, I2D/IG ratio (related to the number of graphene layers) tended to decrease with the reaction time at 1050ºC and with the increase of temperature at the same reaction time. By its part, FWHM (Full Width at Half Maximum) parameter varied between 62 and 76 for 1050ºC and varied between 56 and 67 for the synthesis performed at different temperatures for 25 minutes reaction time. 2D position in the RAMAN spectra is considered an important parameter in graphene characterization because, in -1 the case of graphene, this peak should be displaced to values around 2700 cm if compared -1 with graphite, which is around 2740 cm [5]. In Figure 1 it could be observed the optimum sample of the study, obtained at 1050ºC and 10 minutes reaction time, observing that the defects in the sample are very low. 2D peak deconvulation of sample synthesized at 1050 ºC during 10 minutes originated four different peaks which is a common feature of bilayer graphene [6]. According to the obtained results, a synthesis temperature of 1050 ºC and a reaction time of 10 minutes were selected as the optimum values to carry out the following experiments. Influence of the CH4/H2 ratio. Figure 2 shows RAMAN spectrum and, Table 2 shows the most important RAMAN parameters obtained in the study carried out varying the CH4/H2 ratio in the range 3-45%. As observed, D peak increased and 2D peak even disappeared with the increase of CH4/H2 value. According to the obtained results, the ID/IG and I2D/IG ratio values were the lowest and the highest respectively for a CH4/H2 ratio value of 7%, indicating that the obtained graphene had the lowest amount of -1 both, defects and layers. FWHM value was for this sample of 61 cm and, the 2D peak 1 appeared at 2706 cm- which was in the range generally accepted for graphene. Again, the 2D peak deconvolution showed the presence of the 4 different peaks characteristics in bilayer graphene [6]. Influence of the total gas flow rate. Figure 3 shows RAMAN spectrum and, Table 3 shows the most important RAMAN parameters obtained in the study carried out varying the total gas flow rate in the range 40-140 ml/min. As observed, D peak was practically non-existing for a total flow rate of 60 ml/min and, 2D peak position was displaced to better positions (2706 cm-1) As observed, the lowest ID/IG ratio value was obtained using a total flow rate of 60 ml/min although the I2D/IG ratio was not the higher one. The values obtained for the parameters FWHM and 2D position were not determinant in this study due to they were maintained practically constant.

References: 1.

Nan Li, Z.W.a.Z.S.-E., Dr. Sergey Mikhailov (Ed.), Synthesis of Graphenes with Arc-Discharge Method, Physics and Applications of Graphene 2011. Yao, Y. and C.P. Wong, Monolayer graphene growth using additional etching process in atmospheric pressure chemical vapor deposition. Carbon, 2012. 50(14): p. 5203-5209. Sun, Z., et al., Growth of graphene from solid carbon sources. Nature, 2010. 468(7323): p. 549552. Graf, D., et al., Spatially resolved raman spectroscopy of single- and few-layer graphene. Nano Letters, 2007. 7(2): p. 238-242. Calizo, I., D. Teweldebrhan, y col. (2008), Spectroscopic Raman nanometrology of graphene and graphene multilayers on arbitrary substrates. Journal of Physics: Conference Series 109(1). Ferrari, A. C., J. C. Meyer, y col. (2006), Raman spectrum of graphene and graphene layers. Physical Review Letters 97(18).

2. 3. 4. 5. 6.

Figures: Table 1: Influence of the reaction time at different synthesis temperatures: RAMAN spectroscopy parameter (only the best product at each temperatures are showed)

2D2A

t reaction (min)

ID/IG

1050 1050 1050 1050 1050 1050 1050 1050 900 950 1000

5 10 15 20 25 30 40 45 25 25 25

0,08 0,12 0,14 0,16 0,17 0,22 0,22 0,28 0,29 0,28 0,17

I2D/IG

FWHM -1 (cm )

0,38 0,36 0,32 0,30 0,34 0,33 0,33 0,35 0,32 0,26 0,41

67 67 73 73 62 76 73 73 56 67 65

2D Position -1 (cm ) 2709 2709 2709 2709 2704 2714 2709 2693 2704 2708 2704

2600

1000

1500

0,36 0,38 0,46 0,35 0,37 0,43 0,29 0,04

FWHM -1 (cm ) 62 70 61 62 67 67 67 612

2D Position -1 (cm ) 2714 2711 2706 2714 2714 2709 2714 2730

2000

2500

Intensity (a.u.)

2D2A 2D1B 2600

2650

2D Position -1 (cm )

40 60 100 130 140

0,09 0,09 0,10 0,15 0,14

0,45 0,44 0,39 0,46 0,40

61 61 61 61 61

2713 2706 2706 2706 2711

2D1A 2D2B 2700

2750 -1

Raman Signal (cm )

2800

45% 40% 30% 20% 10% 7% 5% 3%

1000

1500

2000

2500

3000

-1

Raman Signal (cm )

Figure 2: Raman spectrum for the CH4/H2 ratio. Relation conditions: 1050ºC; 10 min; CH4/H2 ratio=3-45%; total flow rate=130 ml/min

2D2A

2D1A Intensity (a.u.)

FWHM -1 (cm )

3000

conditions: 900-1050ºC; 10 min; CH4/H2 ratio=30%; total flow rate=130 ml/min

Intensity (a.u.)

I2D/IG

2800

Figure 1: Raman spectrum for the optimum sample. Relation

Relation conditions: 1050ºC; 10 min; CH4/H2 ratio=7%; total flow rate=40-140 ml/min

ID/IG

2750

-1

Table 3: Influence of the total flow rate: RAMAN spectroscopy parameters

Qtotal (ml/min)

2700

Raman Signal (cm )

Intensity (a.u.)

0,18 0,16 0,15 0,21 0,17 0,17 0,22 0,54

I2D/IG

2650

-1

Relation conditions: 1050ºC; 10 min; CH4/H2 ratio=3-45%; total flow rate=130 ml/min

ID/IG

2D2B Raman Signal (cm )

Table 2: Influence of the CH4/H2 ratio: RAMAN spectroscopy parameters

CH4/H2 (%) 3 5 7 10 20 30 40 45

2D1A 2D1B

Intensity (a.u.)

Tª reaction (ºC)

Intensity (a.u.)

Relation conditions: 900-1050ºC; 5-45 min; CH4/H2 ratio=30%; total flow rate=130 ml/min

2D2B

2D1B 2600

2650

2700

2750

2800

-1

RamanSignal (cm )

140 ml/min

130 ml/min

100 ml/min

60 ml/min

40 ml/min

1000

1500

2000

2500

3000

-1

Raman Signal (cm )

Figure 3: Raman spectrum for the total flow rate. Relation conditions: 1050ºC; 10 min; CH4/H2 ratio=7%; total flow rate=40-140 ml/min

Nanonecklace Structure of Carbon Nanotubes for Ultrahigh Loading Metal Nanoparticles Md. Shahinul Islam,1 Won San Choi,2,* Tae Sung Bae,1 Young Boo Lee,1 and Ha-Jin Lee1,* 1

Jeonju Center of Korea Basic Science Institute, Jeonju, 561-180, Korea Department of Chemical and Biological Engineering, Hanbat Natâ&#x20AC;&#x2122;l University, Daejeon, 305-719, Korea hajinlee@kbsi.re.kr and choiws@hanbat.ac.kr

Abstract We report a simple protocol for the fabrication of nanonecklace structure of multiwall carbon nanotubes (MWCNTs) for loading metal nanoparticles (NPs) in ultrahigh density. MWCNTs have been initially coated with anionic polyelectrolyte (PE), polystyrene sodium sulfonate (PSS) by a noncovalent interaction (MWCNT/PSS). The nanonecklace structures were fabricated by stepwise assembly of both the positively charged poly(allylamine) hydrochloride (PAH) and negatively charged poly(acrylic acid) (PAA) in a nonstoichiometric ratio on the MWCNT/PSS as a template.(Fig. 1a) The zeta potential values and XPS data confirmed the stepwise coating of PEs on MWCNT substrate. It was observed that the PSS did not wrap the MWCNTs in a continuous way but form discontinuous bumps on the surface of the MWCNTs (Fig. 1b). Therefore, when the MWCNT/PSS was employed as a template for additional coating with cationic PAH through electrostatic interaction, some interaction points on the bumps of the MWCNT/PSS can be easily exposed for the next coating. Fig. 1c clearly shows the grown bumps onto the MWCNT/PSS/PAH surface. The MWCNT/PSS/PAH was further coated with anionic PAA, and the necklace structure of MWCNT/PSS/PAH/PAA was obtained (Fig. 1d-f). When the PSS was coated onto the MWCNTs, the thickness of PSS at the bumps was about 8 nm which was 4 times, compared to normal thickness of PSS (approx. 2 nm). This means that the PSS was coated on the MWCNTs as the entangled form and it led to the formation of bump structures on the MWCNTs. We believe that based on the MWCNT/PSS template, the formation of necklace structures was completed by using a nonstoichiometric ratio of PEs (MWCNT/PSS/PAH to PAA). In earlier, we reported a synthesis of self-assembled spherical polyelectrolyte complexes (PECs) in aqueous solution by controlled mixing of PAH and PAA in a nonstoichiometric ratio.[1] The driving force for the formation of spherical PECs is mainly based on the electrostatic interactions between carboxylic and amino groups in a nonstoichiometric ratio. In similar way, nonstoichiometric ratio of PAH to PAA has been applied for the coating of MWCNT/PSS. The necklace structure of the CNT/PSS/PAH/PAA has been employed as a support for loading bi- or tetrametallic NPs such as Au/Ag, Pt/Ag, Au/Pt, Ag/Pd or Au/Pt/Ag/Pd NPs.[1-4] For this purpose, metal precursor-loaded PAH (PAH-Au or Pt ions) and PAA (PAA-Ag or Pd ions) were used to assemble on MWCNT/PSS template instead of bare PAH and PAA, respectively. Control loading of metal precursors ensured that 45-50% and 30-43% of charged groups in the PAH (-NH3+) and the PAA (-COO-) were available for further interactions with opposite charge groups in subsequent steps as we reported earlier, respectively.[4] Therefore, metal precursor-embedded PAH and PAA also enable to construct necklace structure on MWCNT/PSS. After coreduction of multi-metallic precursor-embedded MWCNT/PSS/PAH/PAA by NaBH4, we obtained the corresponding metal NP-decorated nanonecklace structures.(Fig. 2) The nanonecklace structures with highly loaded multi-metallic NPs were demonstrated to be used as catalytic materials for conversion of 4-nitrophenol to 4-aminophenol as well as a convenient SERS substrate for biological tags and molecular detection. We expect that the methodology presented here can be extended to other systems opening up the way of novel applications through synthesis of unique nanostructures. References [1] Md. Sahinul Islam, Won San Choi, Ha-Jin Lee, Young Boo Lee, Il Cheol Jeon, J. Mater. Chem. 22 (2012) 8215. [2] Md. Arifur Rahim, Bora Nam, Won San Choi, Ha-Jin Lee, Il Cheol Jeon, J. Mater. Chem. 21 (2011) 11831. [3] Md. Arifur Rahim, Md. Sahinul Islam, Tae Sung Bae, Won San Choi, Young Yong Noh, Ha-Jin Lee, Langmuir, 28 (2012) 8486. [4] Md. Sahinul Islam, Won San Choi, Young Boo Lee, Ha-Jin Lee, J. Mater. Chem. A, 1 (2013) 3565.

Figures

Figure 1. (a) A schematic representation for the necklace-shaped MWCNTs fabricated by chronological mixing of anionic and cationic PEs in nonstoichiometric ratio. Representative TEM images of (b) MWCNT/PSS, (c) MWCNT/PSS/PAH, and (d) MWCNT/PSS/PAH/PAA. Arrows indicate discontinuous bumps consisting of PEs on MWCNT surface. (e and f) URH-FESEM images of MWCNT/PSS/PAH/PAA.

Figure 2. UHR-FESEM micrographs for bi-metallic NP-embedded p-CNT/PSS/PAH/PAA. Insets are the corresponding STEM images. All scale bars represent 50 nm.

Thermal and electrical interfacial layer of graphene for high performance point emitter

Jeong Seok Lee, Hyelynn Song, Yong Hyup Kim

Seoul National University, Sillim-dong, Seoul, 151-742, Korea misty7@snu.ac.kr

Abstract

With the superior material properties and geometric benefit of high aspect ratio, various researches have been performed to fabricate carbon nanotube (CNT) point emitters which are capable of providing low turn-on voltage, high current density and long-term operating stability [1]. Especially, extremely high field emission current density of the point emitters plays an essential role in generating sufficient power sources for microwave amplifier tubes, high-resolution electron-beam instruments and Terahertz and Xray sources [2]. Moreover, one-dimensional geometry of carbon nanotube point emitter can reduce the operating voltage in the applications due to amplification of field enhancement. However, it is unavoidable in the process that thermal and electrical contact resistances between metal and carbon nanotube would degrade the emission performance, which issues also have been brought up through past studies [3]. Various efforts have been devoted to improving the electric and thermal contacts between metal and carbon nanotube, including the increase of contact surface area using ultrasonic bonder, the reduction of contact resistances by the aid of carbon layer deposition using EBID (electron beam induced deposition equipment) [4] or the formation of graphitic layer via heat treatment at temperature above 880 K [5]. The methods could improve the contact resistances, however, they require high temperature or additional complicated treatments. In the present study, we have used graphene as an interfacial layer between metal and CNT to improve the contact resistances. Single layer graphene has been proven to show remarkable electron mobility (~150,000 cm2/Vâ&#x20AC;˘s) and thermal conductivity (~3100-5300 W/mâ&#x20AC;˘K). Since graphene basically consists of the same material of carbon as CNT and has a similar level of work function (~4.5 eV), our approach can have great advantages of electric and thermal interfaces between these low dimensional carbon materials. With superior electric and thermal contact characteristics created by graphene layer, the present point emitter shows extremely high current density of 2300 A/cm 2, net current of 16 mA and stable, long-term operation over 10 hours.

References

[1] Eric Minoux, NanoLett, 5 (2005) 2135. [2] H. Sugie, Appl.Phys.Lett, 78 (2001) 2578. [3] Nishuang Liu, J.Mater.Chem, 22 (2012) 3478. [4] Konrad Rykaczewski, Nanotechnology, 21 (2010) 035202. [5] Alexander A. Kane, NanoLett, 9 (2009) 3586.

Figure 1.

Figure 2.

Fig 2. (a) I-V plots of point emitter with graphene and without graphene. (b) Field emission stability test of the emitter with graphene and without graphene.

Fig 1. (a) Scanning Electron Micrograph of the point emitter, this is constituted by aligned carbon nanotubes with one direction. (b) Scanning electron micrograph of the emitter with the nail head removed by FIB treatment. (c) Raman spectrum at 532 nm for the cross section of carbon nanotube point emitter of two cases, before FIB and after FIB treatment.

Synthesis and characterization of monodisperse β -cobalt hydroxide using sonochemical method Soo-Keun Lee, A Young Kim Nano & Bio Research Division, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea laser@dgist.ac.kr Abstract β -cobalt hydroxide can be used as an additive to improve the electrochemical activity of alkaline secondary batteries and catalysts because of its unique physical, electric and catalytic properties. Various synthesis methods currently used for the synthesis of β -Co(OH)2 described in the literature

[1],[2],[3]

β -Co(OH)2

typically produce different sizes of β -Co(OH)2. However, we found that monodisperse can

synthesized

sonochemical

method

using

cobalt

nitrate

and

hexamethylenetetramine without addictives. In this case, β -Co(OH)2 have a flat plate-like morphology with diameters of 1µm and thicknesses of several tens of nanometer. However, when cobalt acetate or cobalt chloride were used as cobalt source, monodisperse β -Co(OH)2 was not synthesized. The structural and morphological properties of β -Co(OH)2 were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). References [1] Chaohe Xu, Jing Sun and Lian Gao, CrystEngComm, 5 (2011) 1586-1590 [2] Wenzhong Z. Wang, Qing Zhou, Lijuan Wang, Tao Yang, Guling Zhang, Journal of Crystal Growth, 23 (2010) 3485-3489 [3] Ling-Bin Kong, Jun-Wei Lang, Min Liu, Yong-Chun Luo, Long Kang, Journal of Power Sources, 2 (2009) 1194-1201 Figures

Figure1. SEM images and XRD patterns of Î˛ -Co(OH)2 synthesized by using different cobalt source: (a)cobalt nitrate, (b)cobalt acetate, (c)cobalt chloride.

Acknowledgements This work was supported by the basic research program (13-NB-03) through the Daegu Gyeongbuk Institute of Science and Technology (DGIST), funded by the Ministry of Education, Science, ICT & Future Planning (MSIP) of Korea.

A Novel Approach for Controlling Structure and Size of AgX Nanostructures and Its Application for Visible light-Driven Photocatalyst 1

Yi Seul Lee , Ha-Jin Lee , and Won San Choi * 1

Department of Chemical and Biological Engineering, Hanbat National University, San 16-1, 2 Dukmyoung dong, Yuseong-gu, Daejeon, 305-719, Republic of Korea, Jeonju Center, Korea Basic Science Institute (KBSI), Dukjin-dong 1ga, Dukjin-gu, Jeonju, Republic of Korea E-mail: choiws@hanbat.ac.kr; Fax: +82-42-821-1692; Tel: +82-42-821-1540 Abstract (Arial 10) Ag/AgX (silver/silver halide) has been supposed to be new visible light photocatalytic materials due to its good sensitivity to sunlight. The Ag/AgX catalysts display high photocatalytic activity and stability under 1-2 visible light irradiation due to the SPR of silver nanoparticles produced at the surface of AgX. Recently substantial efforts have been focused on the synthesis of Ag/AgX photocatalysts with high performance 3-4 using facile and versatile methods. However, most of photocatalysts prepared by reported methods are formlessness or spherical structure with irregular shape. Relatively little attention has been directed to controlling structures of photocatalysts into well-defined structure. It has been well-known that nanomaterials with well-defined structures can exhibit unique properties which are not observed in bulk or nanomaterials with irregular structures. Herein, we report a novel approach for controlling structure and size of AgX structures. We report CTAB-decorated AgBr microplates (MPs) that are obtained by mixing silver precursor with hexadecyltrimethylammonium bromide (CTAB) under controlled conditions. By appropriate polyelectrolytes (PEs) coating, it is able to transform structure of AgBr MPs into submicrometer-sized spherical or cubic shape with controlled sizes. We believe that the PEs which posses certain types of functional groups are the crucial factors that control the structure and size of the AgBr MPs. The size and shape-controlled AgBr cubic NPs can be used as plasmonic photocatalysts for the degradation of methylene orange (MO) dyes that are well known for toxic substances under sunlight irradiation. References [1] Zhu M S, Chen P L, Liu M H, Ag/AgBr/graphene oxide nanocomposite synthesized via oil/water and water/oil microemulsions: A comparison of sunlight energized plasmonic photocatalytic activity., Langmuir. (2012) 28, 3385â&#x2C6;&#x2019;3390. [2] L. Kuai, B. Y. Geng, X. T. Chen, Y. Y. Zhao and Y. C. Luo, Facile Subsequently Light-Induced Route to Highly Efficient and Stable Sunlight-Driven Ag-AgBr Plasmonic Photocatalyst., Langmuir. (2010) 26, 18723â&#x20AC;&#x201C;18727. [3] C. Hu, T. W. Peng, X. X. Hu, Y. L. Nie, X. F. Zhou, J. H. Qu, H. He,Plasmon-Induced photodegradation of Toxic Pollutants with Ag-AgI/Al2O3 under Visible-Light Irradation., J. Am. Chem. Soc. (2010) 132, 857-862. [4] Hu C, Lan Y, Qu J, Hu X, Wang A., Ag/AgBr/TiO2 visible light photocatalyst for destruction of azodyes and bacteria., J Phys Chem B. (2006) 110, 4066-4072.

Figures

Synthesis and Catalytic Activity of Gold Nanoparticles Doped Anatase TiO2 Nanoparticles Ana Cláudia Lobão-Nascimento, Jorge Pérez-Juste, Isabel Pastoriza-Santos Departamento de Química Física, Universidade de Vigo, Lagoas-Marcosende, 36310 Vigo, Spain aclobao@gmail.com Since the discovery that gold nanoparticles supported on transition metal oxides, such as titanium dioxide, is a catalyst with unique catalytic performances, gold catalysis has rapidly gained importance attracting many researchers [1–3]. The main aim of the work described here is the synthesis and characterization of a catalyst based on anatase TiO2 nanoparticles uniformly doped with Au nanoparticles, as well as the evaluation of its catalytic properties using as model the electron-transfer reaction between hexacyanoferrate (III) and borohydride ions. The TiO2 mesocrystals (fig.1 a) with a single-crystal like structure and tunable sizes were fabricated on a large scale through mesoscale assembly in the titanium (IV) butoxide-acetic acid system without any additives under solvothermal conditions [4]. The mesoporous channels offer larger surface area and a connect pore system which can help to concentrate molecules for the electron-transfer reactions. It is known that chemical reactions are most effective when the transport paths through which molecules move into or out of the nanostructured materials are included as an integral part of the architectural design. The TiO2@Au catalysts were prepared by the method of deposition-precipitation with urea developed by Zanella and co-workers [5]. TiO2 is decorated with homogenously distributed gold nanoparticles with 4.5 nm of size (Fig. 1b). The close contact between Au nanoparticles and TiO2 allows an effective transfer of electrons from Au nanoparticles to TiO2 core. In order to test the catalysis activity of the TiO2-Au, we employed a model electron-transfer reaction, such as the reduction of hexacyanoferrate (III) by borohydride ions in aqueous solution [6]. In an initial step, the gold nanoparticles surface is rapidly charged by the addition of borohydride. The double-layer charging around the metal nanoparticle facilitates the storage of the electrons on the gold. The electrons migration of the electrons from Au to the conduction band of TiO2 occurs until the equilibration of Fermi level in the entire system is reached. Then, the ferricyanide ions reach the surface of gold and are reduced by excess surface electrons. The progression of the reaction was monitored indirectly through the ultraviolet-visible UV-vis spectrum of hexacyanoferrate (III). The characteristic absorption peak of hexacyanoferrate (III) is located at 420 nm, and its intensity was continuously decreased immediately after the addition of TiO2-Au, revealing the occurrence of catalyzed reduction (Fig. 2). References [1] Haruta, M., Catal. Today, 36 (1997) 153. [2] Haruta, M., Catal. Surv. Jpn, 1 (1997) 61. [3] Bond, G.C.; Thompson, D.T., Catal. Rev. Sci. Eng., 41 (1999) 319. [4] Ye, Jianfeng; Liu, Wen; Cai, Jinguang; Chen, Shuai; Zhao, Xiaowei; Zhou, Henghui; Qi, Limin, J. Am. Chem. Soc., 133 (2011) 933. [5] Zanella, Rodolfo; Giorgio, Suzanne; Henry, C. R.; Louis, C., J. Phys. Chem. B, 106 (2002) 7634. [6] Hervés, P.; Pérez-Lorenzo, M.; Liz-Marzán, L. M.; Dzubiella, J.; Lu, Y.; Ballauff, M., Chem. Soc. Rev., 41 (2012) 5577.

Figures

Absorbance

0,6

(a)

Absorbance

1.0

0,2

0,0 0

Time (s)

Initial 12 s 24 s 36 s 48 s 60 s

0.5

0.0

(b) Figure 1. TEM images of (a) spindleshaped nanoporous anatase TiO2 mesocrystals and (b) TiO2 mesocrystals decorated with 4.5 nm gold nanoparticles.

0,4

300

400 500 Wavelength/nm

600

Figure 2. Spectral evolution of a mixture of hexacyanoferrate (III) and TiO2-Au nanoparticles upon borohydride addition 3-4 -3 ([Fe(CN)6 ]=8.33×10 M, [BH4-]=8.33×10 M, [TiO2-5 Au]=2.27×10 g/mL, T= 25ºC, pH=11.5). Inset: Kinetic trace 3− of the absorbance at 420 nm during Fe(CN)6 reduction.

Thermal expansion of graphite intercalation compounds 1

A. Longo , S. De Nicola , G. Carotenuto , L. Nicolais 4 4 4 4 4 E. Pugliese , M. Ciofini , M. Locatelli , A. Lapucci , R. Meucci 1

Institute for Composites and Biomedical Materials - National Research Council, Naples, Italy 2 SPIN - National Research Council, Naples, Italy. 3 Department of Chemical, Materials and Production Engineering, University “Federico II” of Naples, Naples, Italy. 4 National lnstitute of Optics - National Research Council, Florence, Italy. angela.longo@cnr.it

Graphite and various composite materials based on graphite, including graphite intercalation compounds (GICs), are widely used in a variety of fields of science, technology, and industry [1]. Some GICs with acids and salts are used to obtain thermally expanded graphite (TEG), which has the form of a foamed carbon structure and is used to produce low-density carbon materials[2-4]. Expansion of GICs consists in separating the individual layers in a more or less regular manner, such a separation being sufficient to remove all the inter-planar interaction. For that purpose, the presence of an intercalate is necessary: heating the GICs induces the vaporization of the intercalated species and hence a significant expansion of the material along the crystallographic c-axis occurs [1-4]. Thermal expansion mechanism of GICs is investigated by using infrared (IR) laser irradiation. The specifically designed optical set up allows for measuring the critical temperature which must be exceeded for exfoliation of intercalated graphite flakes (provided by Asbury Carbons) and transition to expanded filaments of graphite flake. An infrared laser at wavelength 1.07 µm was employed to induce a thermal shock and the temperature increase was measured by detecting in the 8-12 µm the midinfrared radiation emitted by a single grain during the heating process. The laser head was positioned in a vertical plane and the laser beam impinges at incident angle 45° on the working surface mounted on an X-Y translation stage (fig. 1 right). The thermal imaging system consisted of a pyro-electric detector array (Pyrocam III by Spiricon Ophir) composed by 124x124 pixels with 85 µm pitch and 100 µm element spacing. This detector is internally chopped and thermal images are recorded by a computer up to a maximum speed of 48 frames/s. The infrared radiation emitted by a grain of graphite flakes was collected and imaged over the detector by means of a germanium close-up lens system, which acted also as a filter for any radiation out of the 8-12 µm range. The whole IR detecting apparatus was mounted on the working surface where the grain was located and it allowed to record 1:1 thermal images of the graphite grains during the laser irradiation process (Fig. 1-left).

CCD Camera

Fig. 1: Experimental setup and thermal image of a graphite grain. Thermal data have been obtained from sequence of recorded IR frames. Fig. (2a) shows a typical three dimensional reconstruction of temperature field form a thermal image of a graphite flake. Fig. (2b) shows the typical temporal evolution of the IR emission from the grain central position during the laser irradiation process. The abrupt increase of the temperature corresponds to a critical transition temperature of the grain of about 160°C.

Fig. 2 Laser induced graphite grain temperature; (a) three-dimensional reconstruction of the spatial distribution of the temperature (Pixel Spacing 100µm);(b) typical temporal evolution of the IR emission from the grain central position during the laser irradiation process The real time temporal evolution of the expansion process is recorded by an high speed (250 frame/s) video camera in the visible range, mounted in the vertical plane orthogonal to the laser beam direction. This camera was equipped with a macro lens in order to obtain greatly detailed images of the grain (37 pixels/mm) and to follow directly the temporal evolution of the laser induced thermal expansion process Fig. (3a) shows the sequence of video frames recorded by the visible camera. These sequence clearly shows the extrusion of graphite filament. The grain increases about 100 times its initial volume and the process is accompanied by vaporization of the intercalated species.

120

Length (pixel)

100

20 0,0

0,1

0,2

0,3

0,4

0,5

Time (sec)

Fig. 3: Temporal evolution of the grain transition. The length of extruded flake is obtained by image processing (Sigma Scan Pro 5) the recorded video frames and its temporal evolution is shown as a function of the irradiation time in fig. (3b). In conclusion we investigated the laser induced thermal exfoliation of graphite intercalation compounds A flexible optical set-up was developed for real time monitoring the extrusion process of the graphite flakes in the visible and the temperature field distribution across the grain size during the laser irradiation process. Temperature measurements performed over different sized grain indicated a critical transition temperature less than 190°. The extrusion process were found to last few seconds depending on the laser irradiation power. References [1] Yakovlev A. V., Finaenov A. I., Zabud’kov S. L., and Yakovleva E. V., Russian Journal Of Applied Chemistry Vol. 79 No. 11 (2006) 1741-1751. [2] Inagaki M., Tashiro R, Washino Y, Toyoda M. , J Phys Chem Solids 65 (2004)133–137. [3] Celzard A., Marêché J.F., Furdin G., Progress in Materials Science 50 (2005) 93–179. [4] Wang S., Tambraparni M., Qiu J., Tipton J., and Dean D. Macromolecules 42 (2009), 5251–5255. Acknowledgment. We are grateful to the Research Project “ENAM - PHYSICAL-CHEMICALBIOTECHNOLOGY FOR ENERGY AND ENVIRONMENT” for financial supporting of this work.

Attenuated total reflection infrared (ATR-IR) spectroscopy in-situ monitoring of the synthesis of bare gold nanoparticles. 1,2

A.I. López-Lorente , M. Sieger , M. Valcárcel , B. Mizaikoff

Department of Analytical Chemistry, University of Córdoba, E-14071 Córdoba, Spain. Phone/Fax +34 957 218616; E-mail: qa1meobj@uco.es 2

Institute of Analytical and Bioanalytical Chemistry, University of Ulm, Ulm, Germany.

Abstract Gold nanoparticles (AuNPs) possess exceptional properties which have promoted their use in many fields, such as biomedical imaging and diagnostic tests, biological applications, catalysts and for uses based on their enhanced optical properties such as absorption, enhanced Rayleigh scattering or surface-enhanced Raman scattering of adsorbed molecules [1]. Infrared spectroscopy has been usually employed until now for the characterization of functionalized gold nanoparticles, due to the vibration features of ligands attached to the nanoparticles. Hartstein at al. [2] reported for the first time the socalled surface-enhanced infrared absorption (SEIRA) effect. Two enhancement mechanisms – electromagnetic and chemical- are thought to mainly contribute to the total enhancement in SEIRA spectroscopy. Electromagnetic mechanism increases the local electric field at the surface and the chemical one assumes an increase of the absorption thanks to chemical interactions between molecules and gold nanoparticles. In this work, photoenhanced adsorption of water on gold nanoparticles has been employed for the insitu monitorization of the synthesis of bare gold nanoparticles by surface-enhanced attenuated total reflection (ATR) infrared spectroscopy. Gold nanoparticles are synthesized directly inside the ATR unit by means of the stainless steel ring forming the walls. While synthesizing, AuNPs adsorb in the SiO2 ATR surface (Figure 1). When increasing the number of gold nanoparticles at surface coverage, Coulomb repulsion from the already adsorbed AuNP film increases and leads to saturation. Despite the IR inactivity of gold nanoparticles, their formation can be monitored by measuring the increase in water absorption bands during the synthesis process, arising from the so-called surface-enhanced infrared absorption (SEIRA) effect. The deposition of gold nanoparticles on the SiO2 ATR surface enhances the absorption signal from water. According to literature [3], the vibrational modes of water in the infrared region are the H 2O bending -1 -1 mode at 1644 cm , the combination of H2O bending and libration at 2128 cm , and one around 3404 -1 -1 cm . This one is composed by the overtone of bending mode at 3250 cm , symmetric OH stretch at -1 -1 3450 cm and the antisymmetric OH stretch at 3600 cm [4]. As gold nanoparticles are formed and deposited on the ATR surface an increase in the H 2O bending (see Figure 2) and the OH stretching bands is observed, despite a decrease in the amount of water molecules present in the evanescent field during the deposition and exchange of water molecules by gold nanoparticles. This increase can be attributed to the so-called SEIRA effect of water molecules in the enhanced field created by formed nanoparticles. This enhanced near-field decays when increasing the distance from the particle surface and it compensates the loss of water molecules replaced by nanoparticles. The influence of gold(III) precursor concentration as well as ATR unit temperature has been investigated. A similar effect has been observed in the case of gold nanoparticles synthesized in deuterium oxide media, the band of deuterium being enhanced during the formation of AuNPs. Moreover, the suitability of infrared (IR) spectroscopy for the investigation of gold solutions has been proved by studying the effect of salts and pH on the aggregation state of gold nanoparticles in solution. Finally, it has been shown that IR spectroscopy can be used to evaluate the sedimentation process of gold nanoparticles on the surface.

References [1] López-Lorente, A.I.; Simonet, B.M.; Valcárcel, M.; Mizaikoff, B. Anal. Chim. Acta 788 (2013) 122128. [2] Harstein, A.; Kirtley, J.R.; Tsang, J.C. Phys. Rev. Lett. 45 (1980) 201-204.

[3] Venyaminov, S.Y.; Pendegast, F.G. Anal. Biochem. 248 (1997) 234-245. [4] Enders, D.; Nagao, T.; Pucci, A.; Nakayama, T.; Aono, M. Phys. Chem. Chem. Phys. 13 (2011) 4935-4941.

Figures

Figure 1. Scheme of the ATR unit employed in this work. As it can be seen the walls of the cell are composed of stainless steel, which acts as reducing agent leading to the in-situ formation of gold nanoparticles from tetrachloroauric acid solution.

Figure 2. In situ ATR-SEIRA H2O bending mode spectra during the synthesis of gold nanoparticles -1 inside the ATR unit in a water environment (from a 200 mg dL HAuCl4 solution).To see the SEIRA effect of gold nanoparticles over water bands, a spectrum of tetrachloroauric acid solution in water just before the synthesis starts was used as background reference. Thus, the water features shown in the spectra are directly the enhancement produced as gold nanoparticles are obtained.

Synthesis of a biofuel that integrates glycerin by using heterogeneous supported KFcatalysts a

a,c

Carlos Luna ; Enrique D. Sancho ; Diego Luna ; Juan Calero ; Gema Cumplido ; Alejandro c a a d b Posadillo ; Felipa M. Bautista ; Antonio A. Romero ; Cristóbal Verdugo ; Salvador Rodriguez . a

Departamento de Química Orgánica, Universidad de Córdoba, Campus de Rabanales, Ed. Marie Curie, 14014, Córdoba, España; b Departamento de Microbiología, Universidad de Córdoba, Campus de Rabanales, Ed. Marie Curie, 14014, Córdoba, España; c Seneca Green Catalyst S.L., Campus de Rabanales, 14014, Córdoba, España; d Laboratorio de Estudios Cristalográficos, Instituto Andaluz de Ciencias de la Tierra, CSIC, Avda. las Palmeras nº4, 18100, Armilla, Granada, España; qo2luduc@uco.es Abstract Our previous researches have allowed to obtain a new type of biofuel, applicable to diesel engines, which integrates the glycerin as monoglyceride (MG), by using 1,3 selective lipases to obtain an incomplete alcoholisis process [1], Figure 1. In order to improve the procedure for the obtaining of this biofuel, given their advantages with respect to the production of conventional biodiesel, the present study aims to access to the same type of biofuel by applying a heterogeneous process in which supported KF is employed as basic catalyst, which has been already described in some organic processes [2] and which has been also recently applied as catalyst for the biodiesel synthesis process [3]. In this respect, it has been investigated the catalytic performance of supported KF at 10% by weight on three different solid supports: alumina, zinc oxide and magnesium oxide. These catalysts were synthesized by impregnating the different supports with a solution of KF in methanol until incipient wetness [2]. The standard experimental conditions employed in the heterogeneous methanolysis reaction were: 0.8 g of catalyst, 12 mL of sunflower oil and 2.7 mL of methanol, operating 1 hour at a temperature of 65 ° C. In all cases with the three supports, 100% conversion values with high selectivity (70-90%) were obtained, as well as quite suitable values of viscosity, 4.6 - 8.4 cSt, although the alumina got comparatively better results (Figure 2). The influence of the catalyst weight has been evaluated by employing variable amounts of KF/Al2O3 (0.2, 0.4, 0.6, 0.8, 1 g) the best catalyst, under standard operating conditions: 12 mL of sunflower oil, 2.7 mL of methanol, 65 ° C temperature and 1 hour of reaction time. The results obtained are shown in Figure 3. The influence of the ratio oil / methanol is determined with a fixed quantity of catalyst, 0.8 g, with 12 mL of sunflower oil and varying amounts of methanol (in mL, 1.2, 1.6, 2, 2.4 and 2.8) operating at 65 ° C of temperature and a reaction time for 1 h. The results obtained are shown in Figure 4, where conversion, selectivity and viscosity of the corresponding values of increased molar ratios of methanol respect to sunflower oil: 1/3, 1/4, 1/5, 1/6 and 1/7 are represented. We can see that the ratio 12/2 in mL, provides the optimum results, which corresponds to a 1/5 molar ratio. These heterogeneous catalysts have resulted therefore to be quite suitable to obtain the partial transesterification of triglycerides (TG) with methanol, so that one molecule of TG generates two moles of fatty acid methyl esters (FAME) and one of MG, operating at heterogeneous conditions, at atmospheric pressure, with a molar ratio oil / methanol of 1/5 and temperatures in the range of 50-65 °C. After optimization of the most appropriate experimental conditions, a biofuel which integrates glycerine as a monoglyceride is obtained in an efficient way, operating in heterogeneous catalytic conditions. Acknowlodgements This research was supported by the Spanish Ministry of Economy and Competitiveness (Project ENE 2011-27017), Spanish Ministry of Education and Science (Projects CTQ2010-18126 and CTQ2011-28954-C02-02), FEDER funds and Junta de Andalucía PO8-RMN-03515 and TEP-7723.

References [1] Luna, D.; Posadillo, A. ; Caballero, V.; Verdugo, C.; Bautista, F.M.; Romero, A. A.; Sancho, E.D.; Luna, C.; Calero, J. Int. J. Mol. Sci., 13 (2012) 10091-10112. [2] Bautista, F.M.; Campelo, J.M.; García, A.; Luna, D.; Marinas, J.M; Romero, A.A.; Journal of the Chemical Society-Perkin Transactions 2, 2 (2002) 227-234 [3] Sharma, Y.C.; Singh, B.; Korstad, J.; Fuel 90 (2011) 1309–1324.

Figure1. Selective ethanolysis obtained through the use of pig pancreatic lipase (PPL).

Figure 2: Influence of the different supports in the viscosity (cSt), conversion (%) and selectivity (%) obtained under standard experimental conditions.

Figure 3. Influence of the catalyst weight (KF/Al2O3) in the catalytic activity parameters: conversion (%) and selectivity (%).

Figure 4. Influence of variable quantities of oil/methanol on conversion, selectivity and viscosity. Increased molar ratios of methanol respect to sunflower oil in mol: 1/3, 1/4, 1/5, 1/6 and 1/7 obtained under standard operating conditions.

The synthesis of porous nano-TiO2 films on the basalt fibers Patrycja Łyczkowska

1,2)

, Małgorzata Cieślak , Grzegorz Celichowski

1) Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, 5/15 Brzezinska Str., 92-103 Lodz, Poland 2) University of Lodz, Department of Materials Technology and Chemistry, 163 Pomorska Str., 90-236 Lodz, Poland. plyczkowska@iw.lodz.pl

The use of nanotechnology offers new capabilities to produce innovative materials for targeted properties, giving them a range of new applications. The photocatalytic properties of TiO2 used to modify the textile materials provide the huge potential application [1,2]. In order to increase the photocatalytic efficiency the smooth TiO2 films may be replaced by porous TiO2 coatings [3,4]. TiO2 was prepared in sol-gel technique using titanium isopropoxide, isopropanol and hydrochloric acid. To the modification of TiO2 - two surfactants hexadecyltrimethylammonium bromie (CTAB) and poly (ethylene glycol) - block-poly (propylene glycol) - block-poly (ethylene glycol) (BLOK) were used. The basalt fibers (diameter 15.2±0.5 µm) with high thermal resistance were used. TiO 2 sol was deposited on the basalt fibers by dip – coating technique. Than the fibers were calcined to obtain photocatalytically active structure – anatase. The form of TiO2 – anatase was confirmed using Raman spectrometer Renishaw InVia. The characteristics of TiO2 coatings on basalt fibers using Scanning Electron Microscope Vega 3 Tescan equipped with X-ray microanalyzer EDS INCA Energy and Atomic Force Microscopy Solver P47 NT-MDT were made. The modified fibers surface and the results of Raman analysis are shown on the Fig.1. The proposed solution allows to obtain porous TiO2 films. As a consequence it caused an increase in the surface area of the photocatalyst compared to smooth TiO2 film. References [1] Chen X., Mao S. S., Chemical Reviews, 107 (2007) 2891; [2] Rahal R., Pigot ., Foix D., Lacombe S. Applied Catalysis B: Environmental 104 (2011) 361 [3] Zhang W., Bai I., Applied Surface Science, 258 (2012) 2607; [4] Bu S. J., Jin Z.G., Liu X.X., Yang L. R., Z. Cheng J., Journal of the European Ceramic Society, 25 (2005) 673.

c) 142

TiO2 on basalt fiber surface The standard of TiO2 â&#x20AC;&#x201C;anatase (Aldrich) 194

394

638 515

Fig. 1 The basalt fibers modified with TiO2 a) smooth film, b) porous film (BLOK), c) Raman map and spectrum of modified fibers.

Acknowledgements The study has been carried out within the Key Project â&#x20AC;&#x201C; POIG.01.03.01-00-004/08 Functional nano- and micro textile materials NANOMITEX co-financed by the European Union with the financial resources of the European Regional Development Fund and the National Centre for Research and Development within the framework of the Innovative Economy Operational Programme, 2007-2013, Priority 1. Research and development of modern technologies, Activity 1.3. Supporting R&D projects for enterprises undertaken by science establishments, Subactivity 1.3.1. Development projects.

Fiber facet reflection modified with a ZnO nanowire array A. A. Machnev, M. Yu. Nazarkin, A. S. Shuliatyev, P. B. Novozhylov, A. N. Belov, D. G. Gromov, and I. V. Mel’nikov Department of Electronic Materials, National Research University for Electronic Technology, proezd 4806, Zelenograd, Moscow 124498, Russian Federation

Abstract: The modification of the end-face reflection for a single-mode fiber is observed and that is due to an array of ZnO nanowires with 40- to 50-nm diameter and 1-micron length deposited there. The small uniform diameter ≤ 100 nm along with low absorption and large refractive index in the visible of wide-gap semiconductor nanowires have opened several avenues for pursuing sub-wavelength optical devices. Among others, ZnO continues to be of particular interest, not only for studies of fundamental solid-state physics but for application to optical waveguides. The practical implementation of ZnO nanowires requires a detailed understanding of coupling external light into the guiding modes of the nanowire whose diameter is much smaller than the corresponding vacuum wavelength. This report presents measurements of broadband light propagating through a single-mode optical silica fiber that has an end facet modified by a deposited array of ZnO nanowires.

The procedure exploited to create an array of ZnO nanowires on a tip of a single-mode optical fiber is based on a standard technological procedure. In order to provide required level of the surface quality, the magneto-sputtering of 300-nm ZnO film is executed immediately after the fiber (SMF-28 Corning) cleaving. This film works as a catalyst for ZnO nanowires to grow and also provides proper adhesion and ordering for the structure to be created in the next step, where lowFigure 1 Technological procedure of a ZnO nanowire array formation on a temperature chemical deposition is used fiber tip to create an array of ZnO nanowires. In the solution, there is a concentration of 0.01 M of Zn(NO 3)2*6H2O and 0.4 M of NaOH, and pH of this solution is equal to 13.2. The solution is kept for ten minutes a water bath heated to 80ºС, and the end facet of the fiber is immersed into it afterwards and kept there for twenty minutes, correspondingly. The fiber with ZnO nanowires grown on its end facet, is cleaned in a deionized water and then air-dried. The 10 length of the nanowire is equal 800 nm, diameter varies from 40 to 50 nm, and surface density is 5x10 2 cm , correspondingly.

Figure 2 The experiment scheme to measure spectral features of the single-mode fiber with an array of ZnO nanowires on its cleaved facet

In the next step, the transmission and reflection spectra of the fiber that comprises a bundle of ZnO nanowires grown on its cleaved facets, are studied using experimental setup depicted in 3+ Fig. 1. The output of the Er broadband source MPB EBS-7210 is launched into one piece of SMF-28 followed by a circulator and another length of the SMF-28 that has ZnO nanowires on its facet and is connected by means of an adapter to the optical spectrum analyzer AQ6370 by Yokogawa. The circulator is introduced into the set-up in order the reflection spectrum to be analyzed simultaneously.

The reflection spectra are measured for the clean cleaved facet, facet with a seed layer of ZnO on its cleaved surface, and with ZnO nanowires that are being grown on this cleaved facet, correspondingly, and the reflection spectrum is given in Figs. 3 and 4. It is readily seen a profound asymmetry in the reflection spectrum that does not

match the transmission one hence making a temptation to claim an observation of surface polaritons excited along the ZnO nanowires. Further basic measurements that are again the spectral measurement but with tilt and variable spacing introduced between the nanowires and collecting fiber confirm this assumption.

Figure 3 Kinetics of the spectrum of the broadband light reflected from the end facet with a seeding layer, where an array of ZnO nanowires is being grown.

Figure 4 The near-IR spectrum of the single-mode fiber that is due to ZnO nanowires of 800 nm length and 40 nm diameter grown on its bare facet

Figure 5 SEM image of the end facet of the single-mode optical fiber with ZnO nanowires grown.

In conclusion, measurements of the transmission and reflection spectra of the single-mode optical fiber that end facet is modified by a disordered (but yet controllable) array of ZnO nanowires, exhibit spectral asymmetry of the reflection due to the excitation of surface polaritons that propagate along the surface of the nanowire. The behavior reported here is of interest for the implementation of new subwavelength optical waveguides.

MWCNTs Based Electrochemical Sensor for Direct Insulin Detection 1,2

1,2

Petra Majzlikova , Jan Prasek , Jana Chomoucka , Jana Drbohlavova , Radim Hrdy , 1,2 1,2 Jan Pekarek and Jaromir Hubalek 1

Department of Microelectronics, Brno University of Technology, Technicka 3058/10, Brno, Czech Republic 2 Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, Brno, Czech Republic businova@feec.vutbr.cz Abstract This work reports on the fabrication of planar multiwalled carbon nanotubes (MWCNTs) based working electrodes suitable for direct voltammetric detection of insulin. Insulin monitoring plays an important role in study of pathophysiology of various disorders especially diabetes. The commonly used assay methods for the determination of this hormone are lengthy, relatively imprecise and insensitive and they cannot be used by clinical laboratories. A direct electrochemical measurement of insulin is of considerable interest in the development of fast and sensitive amperometric detectors which can be coupled to flow systems or chromatographic instruments [1]. Several articles describing direct insulin detection using MWCNTs modified standard electrodes as a sensing element have been reported [2], but no work describing an electrochemical three-electrode MWCNTs based sensor especially made for direct insulin detection have been reported. The aim of our work is to fabricate a disposable electrochemical sensor for direct insulin determination in aqueous solutions (shown in Fig. 1) employing cyclic voltammetry and chronoamperometry in a voltammetric cell against a conventional Ag/AgCl reference electrode and a platinum auxiliary electrode. Our first investigation in this field was focused on MWCNTs based working electrode fabrication and its optimization for insulin detection against common reference electrode and auxiliary electrode. An electrode substrate with contact (DuPont 7102 paste) for the WE was screen-printed on the alumina substrate with dimensions of 25.4 × 7.25 mm and ESL 243-s paste was used as an insulating layer. The standalone WE was spray-coated onto the electrode substrate using an airbrush (Fengda) (Fig. 2) and a mixture of MWNTs dispersed in N,N-dimethylformamide (DMF). SEM image of fabricated working electrode surface is shown in Fig. 3. Electrochemical detection was carried out in a three-electrode voltammetric cell using 0.05 M phosphate buffer solution (pH 7.4) as a supporting electrolyte against common Ag/AgCl reference electrode and platinum auxiliary electrode (both obtained from Metrohm, Switzerland). The cyclic voltammetry in the range of potential from 0 to +1 V using the scan rate of 50 mV/s and chronoamperometry at the potential +0.75 V were performed using PalmSens potentiostat (PalmSens, Nederland). First results obtained using cyclic voltammetry in buffer solution contained 50 μmol/L of insulin at the MWNTs based planar WE (Fig. 4) confirmed our presumption that insulin could be detected on planar spray-coated microelectrodes similarly to modified conventional glassy carbon electrodes which is the first step to fabrication of screen-printed electrochemical sensor. The calibration curve of studied WE in the concentration range from 500 nmol/L to 2.5 μmol/L is shown in Fig. 5. As can be seen, the calibration curve is linear in the studied range of insulin concentrations with the correlation coefficient 2 R =0.9706. References [1] J Wang, et al., Analytica Chimica Acta, 581 (2007), p. 1–6. [2] MG. Zhang, et al, Analytical Chemistry, 77 (2005), p. 6396–01. Acknowledgment This work has been performed in laboratories supported by the operational program Research and Development for Innovation, by the SIX project CZ.1.05/2.1.00/03.0072 and by the project Research4Industry CZ.1.07/2.4.00/ 17.0006 from European Social Fund.

Figures

Figure 1. Designed screen-printed thick film sensor.

Figure 2. MWCNTs based spray-coated WE.

Figure 3. SEM image of MWCNTs based spray-coated working electrode at magnification of 40 kx.

Figure 4. Cyclic voltammograms of MWNTs based working electrode of buffer solution (dashed line) and to 50 Îźmol/L of insulin (continuous line) using a scan rate of 50 mV/s.

Figure 5. Calibration curve of planar spray coated MWNTs based working electrode obtained for the insulin concentrations from 500 nmol/L to 2.5 Îźmol/L.

Vertical nanoelectrode system for potential measurement of living cells a,b*

Marian Márik

a,b

, Vojtěch Svatoš , Jan Pekárek , Jana Chomoucka , Jaromír Hubálek

a,b

LabSensNano, Department of Microelectronics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 3058/10, 616 00 Brno, Czech Republic b Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, 616 00 Brno, Czech Republic *xmarik02@stud.feec.vutbr.cz

Abstract Nowadays the measurement of electrical potential in living cells is a very trendy analysis in the sphere of biotechnology. The cells communicate with each other with the help of electric signals. Additionally based on certain changes in the electrical potential it is possible to observe the reactions of living cells in their life cycles or reactions due to various external influences. The system of measurement must be capable to observe extracellular potential continuously without causing trauma or damage in living cells. Taking into account the above-mentioned requirements a novel vertical nanoelelctrode system for a long term cell analysis in water based medium was designed and realized [1, 2]. The two-electrode system operates on the basis of impedance sensors. Dimensions of electrodes require a combination of micro and nanotechnology techniques for fabrication. For the base of chip a silicon wafer coated with thermal silicon oxide with a thickness 500 nm was used. The first part of realization was the preparation of electrodes for measurement device and the mark for lithography. The electrodes and the mark were made of chromium nickel adhesion layer and PVD (Physical Vapor Deposition) gold layer. The motive was realized with standard UV lithography processes with AZ 5214E resist, and etched with gold etchant standard (Sigma Aldrich) and with NiCr etchant on base of Ammonium Cerium (IV) Nitrate ((NH4)2Ce(NO3)6). After the wet chemical metal etching, the rest of the photoresist mask was stripped away with acetone and isopropanol. The second part of realization was the preparation of vertical nanoelectrodes. The contact between electrodes for measurement device and vertical nanoelectrodes is ensured by two horizontal submicron electrodes with width of 150 nm. To achieve this line resolution at gold structures it is necessary to use accurate etching technique. The most appropriate alternative in this case was etching with focused ion beam (FIB) [3]. The submicron electrodes and the mark for electron beam lithography (EBL) were etched into gold and NiCr layer with FIB. After etching processes the sample was prepared for fabrication of vertical nanoelectrodes in two steps. The first step was coating on the surface of sample PMMA resist, the second step was creating two nano holes into the polymer layer with EBL. The holes must be located over the edge of the horizontal submicron electrodes. The ideal size of holes is 300 nm for depth and 100 nm for diameter. These sizes are based on requirements of measurement method. The measured cell must be electrically isolated from conductive gold layer, and must be in contact with gold nanoelectrodes. The appropriate thickness of PMMA resist for these applications is 300 nm or more. The last part of realization was filling the nano holes with gold. The most accurate method for filling nano holes is voltage controlled pulsed electrochemical deposition of gold. Electrolyte on base of gold potassium cyanide was used for deposition. After the deposition process it was necessary to clean the sample with water and isopropanol. The PMMA layer must not be removed, because it serves as an isolator layer. The structure of prepared system is visible on SEM images (Fig. 1, 2). Acknowledgement This research was supported by the project Research4Industry, the registration number CZ.1.07/2.4.00/17.0006. The described research was performed in laboratories supported by the SIX project; the registration number CZ.1.05/2.1.00/03.0072, the operational program Research and Development for Innovation. References [1] Fraden, J.:Handbook of modern sensors: physics, designs, and applications, New York, Springer Verlag 2004, s. 533-555, ISBN 0-387-00750-4 [2] Cui, Z.: Nanofabrication: Principles, Capabilities and Limits, Didcot, UK, Springer 2008, s. 348 ISBN 978-0-387-75576-2.

[3] Shinji, M., Takashi, K, Junichi, F.,Masanori, K.,Kazuhiro, K.,Yuichi, H.:Three-dimensional nanostructure fabrication by focused-ion-beam chemical vapor deposition, Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures , 2000, s. 3181-3184 Figures

Electrodes for the measurement device

Horizontal submicron electrodes Mark for the lithography processes

Mark for EBL lithography

Fig. 1. SEM image of electrode system (left). SEM macro image of horizontal submicron electrodes (right).

Fig. 2. Details of submicron electrodes and about a place, where vertical nano electrodes are deposited (left). Vertical nano electrode on the edge of the horizontal submicron electrode (right).

Scanning Tunneling Microscopy Analysis of Unusual Moiré Patterns on Graphene on Rh(111) Grown under Ultra-High Vacuum Conditions 1

A. Martín-Recio , A.J. Martínez-Galera 1

1,2

1, 3, 4

and J.M. Gómez-Rodríguez

Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain 2 Present address: Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, Köln, Germany 3 Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid, Spain. 4 Instituto de Física de la materia Condensada IFIMAC, Universidad Autónoma de Madrid, Madrid, Spain ana.recio@uam.es

The growth of graphene on transition metals by means of different procedures has been highly studied in recent years [1, 2]. The main reason why so many efforts have been devoted by the scientific community to study this kind of systems is to understand the interactions between the two dimensional carbon layer and the metal underneath. These interactions do not only change the electronic properties of graphene, but also its geometrical structure which leads to moiré periodic superstructures. It has been found that, if the graphene-metal interaction is low enough, more than one moiré lattice is stable for the same graphene-metal system. In the particular case of graphene grown on Rh(111), this interaction is not considered to be low [1]. Therefore, only one relative orientation of the carbon atom lattice with respect the Rh(111), leading to only one moiré pattern, has been described [3-6]. It is the (12x12) C on (11x11) Rh(111) moiré, in which the carbon lattice is aligned with the metallic one and also with its superstructure. In this study, we report on the growth of graphene on Rh(111) and the formation of several different moiré structures. The experiments have been performed in ultra-high vacuum (UHV) by means of variable temperature scanning tunneling microscopy (VT-STM). Also, the graphene monolayer has been grown on the Rh(111) single crystal in UHV via chemical vapor deposition (CVD) of low pressure ethylene (C2H4). As a result, we have observed the usual (12x12) C on (11x11) Rh(111) moiré which has been already found in previous works (fig. 1), but also several other rotational epitaxial graphene domains (fig. 2). From these data, a relationship between the superstructures’ corrugation and its periodicity has been found. Finally, using this relationship, we compare our experimental results with a simplified model in which both structural and energetic properties of the different moirés have been taken into account.

References [1] M. Batzill, Surf. Sci. Reports 67 (2012) 83. [2] K. Hermann, J. Phys: Condens. Matter 24 (2012) 31410. [3] B. Wang, M. Caffio, C. Bromley, H. Früchtl and R. Schaub, ACS Nano 4 (10) (2010) 5773-5782. [4] E. N. Voloshina, Yu. S. Dedkov, S. Torbrügge, A. Thissen and M. Fonin, Appl. Phys. Lett. 100 (2012) 241606. [5] M. Iannuzzi and J. Hutter, Surf. Sci. 605 (2011) 1360-1368. [6] S. Roth, J. Osterwalder and T. Greber, Surf. Sci. Lett. 605 (2011) L17-L19.

Figure 1. (10x10) nm STM image where the carbon atoms position with respect the (11x11) Rh(111) moiré can be observed and compared with its model on the right part of the figure. Vs= -400mV, IT= 2nA. The distances in the model are set in Å.

Figure 2. (15x15) nm STM image where two different moiré patterns with atomic resolution can be observed: on the right-top part of the STM image the (12x12) C on (11x11) Rh(111) moiré, and on the left-bottom part, a new different moiré pattern. Comparing the angles between both moirés (W) and between the carbon atoms in both flakes (F), a model for the new moiré superstructure has been obtained. Vs= -300mV, IT= 19nA. The distances in the model are set in Å.

Transport Properties of Graphene Decorated with Oxygen Molecules Tomohiro Matsui, Kazuki Nakayama, and Hiroshi Fukuyama Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan matsui@kelvin.phys.s.u-tokyo.ac.jp

Graphene is attracting considerable interests in various aspects. Carries in an ideal graphene sheet behave like the massless Dirac fermions, and exhibit a series of unique electronic properties such as the anomalously quantized Hall effects, the absence of weak localization, and the existence of a minimum conductivity. Moreover, it is a promising material for the future electronics. The high carrier mobility and chemical and mechanical robustness suggest important applications. The next important step of graphene research is to find ways to control the physical properties. One of the strategies is depositing atoms or molecules on graphene. For example, band gap opening due to the chiral symmetry breaking is expected when the adsorbates form the (√3x√3)R30° structure on graphene. On the other hand, it is well known that some adsorbates transfer either electrons or holes into graphene and change the conductance, which makes graphene applicable to gas sensor. To elucidate the mechanism of the chemical doping, Sato et al. [1] measured the two-terminal conductivity of bilayer (BL) graphene when it is exposed to 1 atm of molecular oxygen (O2) at room temperature. They repeated the O2 exposure with a short-time interval at a certain gate voltage (Vg) and measured a Vg dependence of conductivity after evacuating the O2 gas. They showed that the hole doping proceeds faster at higher Vg, and the doping rate follows a power-law in time rather than exponential. They also noticed that the Vg dependence of conductivity is restored by annealing graphene in vacuum at 200 ℃. Here, we studied the effect of O2 exposure on both monolayer (ML) and BL graphene samples which are installed in a vacuum chamber. Three ML and one BL graphene samples were fabricated by micromechanical cleavage on a surface SiO2 layer of 285 nm thick of a highly doped Si which is used as a back gate electrode. The thickness of graphene samples were determined both from the contrast of green component in optical microscope image and the Raman spectroscopy. The time evolution of conductivity was measured by sweeping Vg within ± 10-25 V about the Dirac point (DP) under a fixed pressure of O2 of 200-500 Pa at room temperature. Since the surface cleanness is extremely important to study the effect of adsorption, micro-electrodes of fine indium wires were soldered directly onto graphene [2] as shown in fig. 1(a). This so-called the dry process may keep the graphene surface as was exfoliated without contaminations of resist residue or solutions in ordinary wet process like photolithography. Not to measure the contact resistance of the indium electrodes, the conductivity was measured with four-terminal configuration. Figure 1(b) shows a measured Vg dependence of resistance (R) in one of the ML graphene samples during the O2 exposure, in which the shift of DP is marked with the red circles. One can easily see that both the energy (VDP) and resistance (RDP) at the DP increase monotonically by time. In addition, the RVg curve is modified by the O2 exposure. We analyzed the data in terms of the shift of DP (∆VDP), RDP and resistance drop (∆R) from the DP at Vg = VDP ± 5 V. Here, positive ∆Vg means hole doping, while larger RDP indicates increasing scattering centers. On one hand, the increasing ∆R or sharpening of the R-Vg curve naively suggests higher mobility. Figure 2 shows measured time evolutions of ∆VDP, RDP and ∆R for BL (a)-(c) and for ML graphene 5

(a)

R (k)

ML graphene

(b)

Indium electrodes

20 μm

t = 149 hrs

t=0

3 2 1

ML graphene in O 2 of 480 Pa, at R.T.

0 -30

-20

-10

Vg (V)

Figure 1. (a) Optical microscope image of a ML graphene sample with indium microelectrodes. (b) Resistance of ML graphene as a function of Vg before (t = 0) and 149 hours after exposing to an O2 gas of 480 Pa. The change of the Dirac point during the O2 exposure is represented by the red circles.

(d)-(f). As shown in fig. 2(a), ∆VDP(t) for BL graphene follows a power-law in time rather than exponential as reported previously [1]. The power (~0.25) is also comparable to the previous report [1]. We found that ML graphene has a similar time dependence but with a roughly two times larger power (~0.5) than in BL graphene. This suggests stronger chemical reaction with O2 due perhaps to larger deformation by SiO2 substrate in ML than in BL graphene, which is consistent with the fact that oxidative etching of graphene in O2/Ar environment proceeds at lower temperature in ML (~450 ℃) than in BL (~600 ℃) graphene [3]. On the other hand, RDP and ∆R are found to behave rather differently from ∆VDP and showed strong sample dependence. At first glance, since adsorbed O2 would act as scattering centers in transport, one may expect that RDP should increase and ∆R should decrease in time. However, as shown in fig. 2(c), ∆R sometimes increases in time. While RDP and ∆R of ML graphene change gradually in time (figs. 2 (e)(f)), those of BL graphene change rather rapidly and saturate as shown in figs. 2 (b)(c). The changes of ∆VDP, RDP and ∆R caused by the O2 exposure are restored only partially even after evacuation of the chamber with samples at about 100 ℃ for 6 to 70 hours, and the subsequent O2 exposure provides smaller changes. Such a tendency seems to continue at least up to five O2 exposure/evacuation cycles. These results probably indicate the existence of qualitatively different adsorption or catalytic sites for adsorption or dissociation such as defects, edges, etc., and adsorption processes such as surface diffusion, chemical reaction, etc. In this presentation, we will also show strong temperature dependence of conductivity in graphene exposed to O2 at room temperature down to T = 1.6 K. The resistivity decreases slowly with decreasing temperature until ~80 K, below which it turns to increase with a dependence of R ∝ exp(T-1/3) suggesting the variable range hopping in two dimensions. In addition, a complicated structure with many sharp peaks appears in the Vg dependence in this low temperature regime. The peak amplitude becomes larger at lower temperatures. It suggests stronger localization of carriers at low temperatures after the O2 adsorption.

VDP (V)

3 10

2 1

0 5.1

0 4.6

4.4

4.9

4.2

RDP (k)

(d)

(a)

4.8

(e)

(b)

4.7 15

R ()

3.8 70 60

50 5

time (hr.)

(f) 0

100

150

time (hr.)

References [1] Y. Sato, K. Takai, and T. Enoki, Nano Lett., 11 (2011) 3468. [2] Ç. Ö. Girit and A. Zettl, Appl. Phys. Lett., 91 (2007) 193512. [3] L. Liu et al., Nano Lett., 8 (2008) 1965.

Figure 2. Time evolution of ∆VDP, RDP and ∆R for BL graphene after exposing to an O2 gas of 480 Pa (a)(c) and for ML graphene to O2 of 416 Pa (d)-(f) at room temperature. The data in (d)-(f) are extracted from those shown in fig. 1(b). ∆VDP varies with a power-law in time for both ML and BL, while time dependences of RDP and ∆R vary sample to sample.

Self Assembled Monolayers over Ferromagnetic Surfaces M. Mattera1, A . Forment-Aliaga1, S. Tatay1.2 , E. Coronado1 1 Unidad de Investigación de Materiales Moleculares, Instituto de Ciencia Molecular, 46980 Paterna, Spain 2 Unité Mixte de Physique CNRS/Thales associée à l’Université Paris-Sud, 91767 Palaiseau, France michele.mattera@uv.es

Self-assembled monolayers (SAMs) consist of organized assemblies formed by the spontaneous adsorption of their molecular constituents from solution (or vapor phase), onto solid surfaces [Figure 1].[1] SAMs have well defined structures, are lightweight, flexible, nanometer thick and its properties can be tailored by chemical synthesis. Such characteristics make SAMs valuable high quality interface layers in electronic devices.[1b] For that purpose well known grafting protocols for the functionalization of surfaces like, Silicon or Gold[1c] have been used. When it comes to spintronics, SAMs expected long spin life-time and the possibility of working at high bias[2] make them promising candidates as tunnel barriers. In this case, traditional nonmagnetic electrodes have to be replaced by ferromagnetic metals. However, in the literature we can find just a few examples of SAMs formation over ferromagnetic materials[2b-d] like Cobalt[2e], Nickel[2f] or LSMO[2a]. So, as a previous step to definitely foster the integration of SAMs as spintronics barriers, the missing grafting protocols have to be developed. Permalloy (Py) is a ferromagnetic nickel–iron alloy, commercially available and currently used in magnetic storage technology, that features high permeability, small coercivity, near zero magnetostriction and significant anisotropic magnetoresistance.[3] In spite of its interest, as far as we know, there is not previous report in the literature about the growth of SAMs on it. Py, like most ferromagnetic materials, when exposed to air develops a thin oxide layer that covers the surface and prevents further oxidation. We decided to take advantage of this oxide as a binding layer for the formation of SAMs. In this work we report a successful method for grafting alkylphosphonic acids (CnP = CH3(CH2)n-1PO3H2, n = 12, 14, 16, 18) onto Py surfaces. In this process the previous activation of the surface with hydrogen plasma resulted critical. During our study the quality of formed layers has been carried out by means of dynamic water Contact Angle (CA) [Figure 2] , Atomic Force Microscopy (AFM) [Figure 3], X- Ray Reflectometry (XRR) and X-Ray Photoelectron Spectroscopy (XPS).

References

a ‐ Love, J.C., et al., Self‐Assembled Monolayers of Thiolates on Metals as a Form of Nanotechnology. Chemical Reviews, 4 (2005): p. 1103‐1170; b ‐ Zschieschang, U., et al., Mixed Self‐Assembled Monolayer Gate Dielectrics for Continuous Threshold Voltage Control in Organic Transistors and Circuits. Advanced Materials, 40 (2010): p. 4489‐ 4493; c ‐ Ulman, A., Formation and structure of self‐assembled monolayers. Chemical Reviews, 4 (1996): p. 1533‐1554. a ‐ Tatay, S., et al., Self‐Assembled Monolayer‐Functionalized Half‐Metallic Manganite for Molecular Spintronics. ACS Nano, 10 (2012): p. 8753‐8757; b ‐ Wang, W. and C.A. Richter, Spin‐polarized inelastic electron tunneling spectroscopy of a molecular

magnetic tunnel junction. Applied Physics Letters, 15 (2006): p. 153105‐3; c ‐ Petta, J.R., S.K. Slater, and D.C. Ralph, Spin‐Dependent Transport in Molecular Tunnel Junctions. Phys Rev Lett, 13 (2004): p. 136601; d ‐ Hoertz, P.G., et al., Comprehensive Investigation of Self‐Assembled Monolayer Formation on Ferromagnetic Thin Film Surfaces. J Am Chem Soc, 30 (2008): p. 9763‐9772; e ‐ Devillers, S., et al., 1‐ Dodecanethiol Self‐Assembled Monolayers on Cobalt. Langmuir, 24 (2011): p. 14849‐ 14860; f ‐ Mekhalif, Z., et al., Elaboration of Self‐Assembled Monolayers of n‐ Alkanethiols on Nickel Polycrystalline Substrates: Time, Concentration, and Solvent Effects. Langmuir, 3 (2003): p. 637‐645. a ‐ Nicholson, D.M.C., et al., Magnetic structure and electronic transport in permalloy. Journal of Applied Physics, 8 (1997): p. 4023‐4025; b ‐ Nahrwold, G., et al., Structural, magnetic, and transport properties of Permalloy for spintronic experiments. Journal of Applied Physics, 1 (2010): p. 013907‐6.

Figures

C12P C16P C18P

120

Contact Angle ()

100

0 0

Figure 1 Self assembled Monolayer Scheme

Figure 2 Dynamic Water Contact Angle measurements of C12P, C16P and C18P.

Figure 3 AFM image of a C16P SAM over Permalloy

Run

Extraordinary transmission through complex periodic structures Agn`es Maurel

Simon Felix

Jean-FrancÂ¸ois Mercier

Inst. Langevin, 1 rue Jussieu, Paris, France Email: agnes.maurel@espci.fr

LAUM, CNRS, UniversitÂ´e du Maine, av. O. Messiaen, Le Mans, France Email: simon.felix@univ-lemans.fr

Poems, CNRS, ENSTA ParisTech, 828 bld des MarÂ´echaux, Palaiseau, France Email: jean-francois.mercier@ensta-paristech.fr

Broadband perfect transmission through sub-wavelength gratings is analyzed in terms of homogenized medium. The gratings consist in a periodic microstructure made of a penetrable material, say a dielectric structure; limiting cases include the Neumann case (hard material) and the non magnetic case (electromagnetic waves in dielectric material). The enhanced transmission of waves impinging at oblique incidence on such grating is shown to occur at an optimal angle depending on the contrasts between the grating material and the host medium, a limiting case being the already reported Brewster angle. The effect of the geometry of the grating is considered, revealing a strong dependence of the transmission spectrum on this parameter, beyond the usually considered filling fraction.

Transmission and localization length through 1D periodic system with disorder Agnès Maurel & Paul A. Martin, Institut Langevin, ESPCI, 1 rue Jussieu, Paris-France Colorado School of Mines, Golden- USA agnes.maurel@espci.fr

Abstract The study of disordered photonic crystals has experienced an increasing interest in recent years because of their potential applications, notably to build new transducers. More recently, Anderson localization in disordered graphene system has been reported [1] and interesting phenomena have been revealed, as the Anderson insulators behvior of graphene nanoribbons [2], the localization of Dirac quasi particule in relation with the Klein paradox [3] or the suppression of Anderson localization in graphene sheet [4]. We report the study of the localization length and of the transmission through 1D periodic systems with delta potentials perturbed with both positional and compositional disorders. The use of the Coherent Potential Approximation (CPA) allows to identify, in addition to the localization length, the whole structure of the Bloch-Floquet mode in this perturbed but periodic-on-average system. This allows to calculate a transmission coefficient that accounts for the internal reflexion inherent to the propagation in finite size system, beyond the usual prediction T= exp(-x/L), with L the localization length. Comparison of our predictions with previous works [5] and with direct numerical calculations are reported (Fig. 1 and 2).

References [1] Q. Zhao, J. Gong and C. A.. Müller, Phys. Rev. B 85, 104201 (2012). [2] D. Querlioz, Y. Apertet, A. Valentin, K. Huet, A. Bournel, S. Galdin-Retailleau, and P. Dollfus, Apllied Phys. Lett. 92, 042108 (2008). [3] J. Yuan, Z. Cheng, M. Yin, Q. Zeng and J. Zhang, Commun. Theor. Phys., 54, 1129–1133 (2010) [4] H. Jiang, J. Zhang, Z. Wang, Y. Li and H. Chen, Physics Letters A 376, 1509–1514 (2012). [5] F.M. Izrailev, A.A. Krokhin and N.M. Makarov, Phys. Rept. 512, 125–254 (2012).

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0.4 length 0.4 Fig. 2: 1: . Transmission Transmission a function frequency aN1D= periodic presence FIG. |Tas a functionofofthe kd/π in a slabthrough of 50. Left system column, in forthe increasing in �,offrom top to N | as 0.4 0.4 0.2 0.2 disorder. is a wave propagating through periodic delta potentials with perturbation in bottom � =The 0.1, system 0.14, 0.34 and 1. Right column, for increasing ξ, from top to bottom ξ = 0.01, 0.3, 0.6 and 1. the Blue symbols 0.2 0.2 3 d/Lloc 0 0 0(compositional 0.2 0.4 0.6 0.8 1 0 0.1 0.2 Nr 0.3 = 0.4 0.5 0.6 0.7 averages, 0.8 0.9 height 1red curve position (positional and in the potential disorder). Blue symbols: direct numerical calculations with 10 ensemble |T | from (22) and green curves |T | e−N , N QCA N 0 loc 0disorder) FIG. 2: . Transmission |TN | as a function kd/π 50. 0.2Left column, in �, from =top to 0 0.4 0.8 1 0 0.1 0.2 of 0.3 0.4 0.5 a0.6slab 0.7 of 0.8 length 0.9 1 N = kd/π 0.6 for increasing kd/π in kd/π with 1/Lloc =calculations, Im(Kd) in (12). numerical ref curves:kd/πour CPA prediciton for the transmission, Green curves: usual 0.6

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bottom � = 0.1, 0.14, 0.34 and 1. Right column, for increasing ξ, from top to bottom ξ = 0.01, 0.3, 0.6 and 1. Blue symbols prediction transmission based onaverages, the localization length exp(-x/L). −N d/Lloc numerical calculations with Nr = 103 ensemble red curve |TN |T= , QCA from (22) and green curves |TN |loc = e Left: Effect of the increasing positional disorder. 2: . Transmission |T | as a function of kd/π in a slab of length N = 50. Left column, for increasing in �, from top with 1/Lloc FIG. = Im(Kd) in (12). N FIG. 2: .Right: Transmission |TNthe | asincreasing a function of kd/π in a slabdisorder. of length N = 50. Left column, for increasing in �, from top toto Effect of compositional bottom � = 0.1, 0.14, 0.34 and 1. Right column, for increasing ξ, from top to bottom ξ = 0.01, 0.3, 0.6 and 1. Blue symbols bottom � = 0.1, 0.14, 0.34 and 1. Right column, for increasing ξ, from top to bottom ξ = 0.01, 0.3, 0.6 and 1. Blue symbols 3 3 −N d/Lloc d/L loc , , numerical calculations withwith Nr N =r 10 averages, |QCA curves |T |TNN||loc =ee−N NN loc = numerical calculations = 10ensemble ensemble averages,red redcurve curve|T|T |QCAfrom from (22) (22) and and green green curves with with 1/Lloc =locIm(Kd) in (12). 1/L = Im(Kd) in (12).

FIG. 3: Errors on the |TN | estimate as a function of the disorder strength and as a function of kd. Top, the error is |TN |−|TN |QCA normalized with |TN | (left column for a disorder in � and right column for a disorder in ξ). Bottom, the error is |TN |−|TN |loc same representation.

FIG. 3: Errors on the3:|TErrors asNa| estimate functionasofa the disorder and as aand function of kd.ofTop, the error is |T |QCA N | estimate NN FIG. on the |T function of thestrength disorder strength as a function kd. Top, the error isN|T|−|T |QCA N |−|T IV. CONCLUSION FIG.normalized 3: NErrors the|T|T | estimate ain function ofinthe disorder strength as function of kd. is |TN |−|T |QCA normalized with |T | (lefton column a disorder and right a disorder in aξ). Bottom, theTop, error is error |TisN|T|−|T |Nloc|loc same with |for (left columnasfor a �disorder � column and rightfor column forand a disorder in ξ). Bottom, the the error same N NN N |−|T Fig. 2: with 2D|Trepresentation ofathe errorin(in log10 scale) between the prediction transmission and normalized disorder � and right column for a disorder in ξ). Bottom, the error isvalue |TN |−|T representation. N | (left column for N |loc same representation. the referencelike: value as aindicator functionofofthe theeffect amount of disorder disorder but (vertical, in log10 the finite representation. Something the(calculated localizationnumerically), length is a good of the that disregards scale) and as a function of the frequency (horizontal). size effects. QCA approach allows to get a prediction on |TN | that accounts for the oscillations on |TN | due to internal Left: for positional disorder. IV. CONCLUSION IV. CONCLUSION Right: for compositional disorder. IV. CONCLUSION Something like: the localization length is a good indicator of the effect of the disorder but that disregards the finite Something Something like: the localization length islength a to good ofonthe effect of theofdisorder but but thatthat disregards theinternal finite size effects. QCA allows getisaindicator |TNof | that accounts for the oscillations on |T N | due to the like: theapproach localization aprediction good indicator the effect the disorder disregards finite size effects.size QCA approach allows to get a prediction on |T | that accounts for the oscillations on |T | due to internal N on |TN | that accounts for the oscillations on N|TN | due to internal effects. QCA approach allows to get a prediction

Surfing plasmonic waves Plasmonic crystal based solid substrate for Surface Enhanced Raman Spectroscopy Dora Mehn, Carlo Morasso, Silvia Picciolini, Renzo Vanna, Marzia Bedoni, Furio Gramatica Fondazione Don Carlo Gnocchi ONLUS, 66 Via Capecelatro, 20148 Milano Italy Paola Pellacani, Ana Frangolho, Gerardo Marchesini, Andrea Valsesia Plasmore S.r.l., 4 Via Deledda, 21020 Ranco Italy dmehn@dongnocchi.it Abstract The optical properties of nanoparticles used for enhancement of Raman signals in Surface Enhanced Raman Spectroscopy (SERS) strongly depend not only on the composition, shape and size of the particles, but also on the properties of the surrounding medium. Complex multistep synthesis methods are applied to prepare monodispersed, coated or core-shell particles that resist of aggregation, of aspecific binding of analytes or allow to collect them by external magnetic fields for easy separation and concentration [1]. Nanohole array based solid SERS substrates help to overcome these difficulties. They provide a regularly distributed array of hot spots and offer the facile phase separation advantage of heterogeneous reaction systems. In these structures, enhanced electrical field is generated when incident light excites an active plasmonic mode of nanoholes, which can be exploited for several plasmonic applications. The availability of cheap, reliable and easy to use substrates would pave the road to the development of bio-analytical tests that can be used in clinical practice. SERS based analysis of biomarkers is expected to provide not only higher sensitivity [2] and specificity, but also multiplexing capacity and markedly improved detection speed compared to the conventional analytical methods [3]. Several studies forecast the potential of Raman-SERS to yield innovative biotechnological applications in the field of cancer diagnosis and monitoring [4-6]. We present here the SERS activity of 2-D plasmonic crystals deposited by the combination of softlithography and plasma deposition techniques on transparent substrates. The special lithographic process enables accurate control of the structural and chemical parameters of the crystal surfaces. In this way the plasmonic resonance spectral position was tuned to the excitation wavelength of the monochromatic light source. Samples were characterized by atomic force microscopy, scanning electron microscopy, reflectance measurements and tested for SERS activity using known Raman reporter dye molecules. The transparent support material allowed SERS detection from support side opening the possibility to use these substrates combined with microfluidic devices. In order to demonstrate the potential for bioanalytical applications, the SERS active gold surface was functionalized with thiol modified (ssDNA) capture oligonucleotides. Concentration dependent signal of a complementer, Raman-reporter labeled target nucleotide (21 bp WT1 gene sequence) was detected on the surface after annealing reaction. Based on our results, the excellent Raman enhancing properties accompanied by the ease of functionalization as well as controllability and low cost of the production procedure make this kind of nanostructures promising candidates for bioanalytical applications.

References [1] H.T. Zhang, J. Ding, G.M. Chow, Z.L. Dong, Langmuir, 24 (2008) 13197-202. [2] D. Graham, Angew. Chem. Int. Ed. 49 (2010) 9325 – 9327. [3] C. Kirschner, K. Maquelin, P. Pina, N.A. Ngo Thi, L.P. Choo-Smith, G.D. Sockalingum, C. Sandt, D. Ami, F. Orsini, S.M. Doglia, P. Allouch, M. Mainfait, G.J. Puppels, D. Naumann, J. Clin. Microbiol. 39 (2001) 1763-70. [4] C.T. Nguyen, J.T. Nguyen, S. Rutledge, J. Zhang, C. Wang, G.C. Walker, Cancer Letters 292 (2010) 91–97. [5] K. Hering, D. Cialla, K. Ackermann, T. Dörfer, R. Möller, H. Schneidewind, R. Mattheis, W. Fritzsche, P. Rösch, J. Popp, Anal. Bioanal. Chem. 390 (2008) 113–124. [6] G.L. Liu, F.F. Chen, J.A. Ellman, L.P. Lee, Conf. Proc. IEEE Eng. Med. Biol. Soc. 1 (2006) 795-8.

Figures

Figure 1: Nanohole array and tunable parameters

Figure 2: Tuning of the structure by changing geometric parameters

active surface support side detection Relative intensity

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Figure 3: SERS detection of dried malachite green drop from active surface and support side on the nanoarray substrate.

Towards Molecular Printboards with Improved Electrical Contact: Tuning the Self-Assembly Capabilities on Gold of β-Cyclodextrin Derivatives Through Chemical Functionalization. A. Méndez-Ardoy, T. Steentjes, T. Kudernac, P. Jonkheijm, J. Huskens. Molecular Nanofabrication Group, MESA+ Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands a.mendezardoy@utwente.nl Abstract Self-assembly at solid substrates constitutes an important strategy to tune the interfacial properties of a range of materials[1]. Chemical manipulation of the building blocks can be used to drive the assembly process and consequently gain control over the resulting properties, which is essential in the development of molecular electronics[2]. In this sense, the immobilization of host molecules is highly appealing since selective and precise but reversible positioning of guests is possible. β-Cyclodextrin (βCD)-based molecular printboards have been prepared by functionalization of the primary rim with long alkyl-sulfide chains that mimic the assembly behavior of alkanethiols[3], yielding densely packed monolayers exposing the β-CD moiety at the surface. However their potential use in applications where the electron transfer to or from the electrode is required is limited because the thick alkyl layer restricts electron transfer. Here we report an alternative strategy for promoting self-assembly based on the incorporation of weak gold-binding functional groups directly on the primary rim of the β-CD core, taking advantage of the directional, multivalent exposure of the anchoring groups to increase the affinity and stability of the interaction. The assembly of these adsorbates has been characterized by contact angle goniometry, surface plasmon resonance (SPR), polarization modulation infrared reflection adsorption spectroscopy (PM-IRRAS), X-ray photoelectron spectroscopy (XPS) and electrochemistry, strongly supporting the presence of these compounds at the surface. The role of the anchoring group demonstrated a strong influence on the adsorption kinetics, film thickness and order of the resulting monolayers.

References [1] Love, C. J.; Estroff, L. A.; Kriebel, J. K.; Nuzzo, R. G.; Whitesides, G. M., Chem. Rev., 105 (2005) 1103. [2] Lu, W.; Lieber, C. M., Nat. Mater., 6 (2007) 841. [3] Beulen, M. W. J.; Bügler, J.; Lammerink, B.; Geurts, F. A. J.; Biemond, Ed M. E. F.; van Leerdam, K. G. C.; van Veggel, F. C. J. M.; Engbersen, J. F. F.; Reinhoudt, D. N., Langmuir, 14 (1998) 6424.

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Study of topological defects in graphene J.P. Méndez, M. Ortiz, M.P. Ariza Escuela Técnica Superior de Ingeniería, Universidad de Sevilla, Camino de los Descubrimientos, s/n. Isla de la Cartuja, 41092, Sevilla, Spain

jmendez@us.es Abstract

We present an assessment of the stability of defects at finite temperature and how the transport properties can be modified by the inclusion of defects in graphene. Additionally, we also exhibit the power of the discrete dislocation theory (DD) developed by Ariza&Ortiz [1,2] to predict easily and reliably harmonic displacement field of defects. In particular, we study the stability of different defects, such as dislocation quadropole and dipole arrangements [3], stacking faults [4], partial dislocations [4] and grain boundaries against annihilation. Most of these defects have been observed stable [5,6] in graphene. In order to carry out this study, we first use the theory of discrete dislocation to compute the harmonic atomic structure of defects, employing for this, either linearized empirical potentials such as Airebo [7] and Aizawa [8] or linearized semi-empirical potential such as tight binding [9]. The benefit of the latter is that we can predict electronic properties due to defects and also requires less computational time than ab initio simulations. Tight binding potentials represent a compromise between ab initio and empirical potentials. Straight afterwards, using LAMMPS code (Sandia National Laboratories Largescale Atomic/molecular Massively Parallel Simulator) and the defective configuration predicted by discrete dislocation theory as initial condition, we study the stability of defects at finite temperature. As a result, on one hand, we predict high stability of dislocation dipole and quadropole configurations against annihilation, unlikely dissociation of perfect dislocations into partial dislocations in graphene and change of electronic properties due to defects. On the other hand, we demonstrate the ability of the discrete dislocation theory to predict defective configurations.

References [1] Ariza, M.P.;Ortiz, M., Archive for Rational Mechanics and Analysis, 178 (2005) 149-226. [2] Ariza, M.P.;Ortiz, M., Journal of the Mechanics and Physics of Solid, 58 (2010) 710-734. [3] Ariza, M.P.; Ortiz, M;Serrano, R., International Journal of Fracture, 166 (2010) 215. [4] Ariza, M.P.; Serrano, R. Mendez J.P.; Ortiz M., Philosophical Magazine, 92 (2012) 2004-2021. [5] Rutter, G.M.; Crain, J.N.; Guisinger, N.P.; Li, T.; First, P.N.; Stroscio, J.A. Science, 317 (2007) 219222. [6] Hashimoto, A.; Suenaga, K.; Gloter, A.; Urita, K.; Iijima, S., Nature, 430 (2004) 870-873. [7] Stuart,SJ; Tutein, AB; Harrison, JA., Journal of chemical physics, 112 (2000) 6472-6486. [8] Aizawa, T; Souda, R.; Otami, S; Ishizawa, Y; Oshima, C., Physical Review B, 48 (1990) 1146911478. [9] Xu, C.H.; Wang, C.Z.; Chan, C.T.; Ho, K. M., Journal of Physics: Condensed Matter, 4 (1992) 60476054.

Electronic structure of InN-based nanowires using multiband k · p envelope function method obal Heruy Taddese Mengistu and A. Garc´ıa-Crist´ Institute de Ciencia dels Materials, Universitat de Valencia,46980 Paterna (Valencia), Spain E-mail: heruy.mengistu@uv.es

Group III nitride materials are well known for their excellent optical and electronic properties. Among these compounds, InN possesses the narrowest bandgap, the smallest effective electron mass, and the highest electron mobility. Moreover, the recent advances in the fabrication methods allow the growth of InN, ternary Inx Ga1−x N, and InGaN/GaN heterostructure in nanowire-like geometry. Due to these unique properties, the wurtzite InN-related nanowires are promising systems for applications in energy harvesting [1] and optoelectronic nanodevices [2]. In general, wurtzite semiconductors have a complicated valence band structure, and in the special case of InN, several studies have reported also a strong non-parabolicity of the conduction band [3]. In the case of InN-based core-shell nanowires, the strain also alters the band structure. All these factors make difficult the analysis of experimental results, and theoretical models are demanded to understand the trends in the electronic and optical properties of nanowires. In this work we propose a multiband k · p envelope function method to study the electronic structure of InN-based nanowires. We report on the electronic states, optical matrix elements and optical absorption of infinitely long cylindrical free standing InN nanowires and InN-based core-shell nanowires (see figure below). We present an analysis of the symmetry of the valence and conduction states, as well as the effect of size and strain on the nanowire band gaps.

(a)

(b)

Figure 1: (a) and (b) show conduction and valence bands of cylindrical InN nanowire, R = 20 nm . This work has been supported by the European Union through the Grant Agreement No. 265073NANOWIRING of the Seventh Framework Program.

References [1] Ku, N.J., Wang, C.H., Huang, J.H., Fang, H.C., Huang, P.C. and Liu, Adv. Mater., 25:936 (2013) [2] C. T. Huang , J. Song , C. M. Tsai , W. F. Lee , D. H. Lien , Z. Gao , Y. Hao , L. J. Chen , Z. L. Wang , Adv. Mater.22 , 4008 (2010) [3] Antanas Reklaitis, J. Appl. Phys. 112, 093706 (2012)

Fano type resonance in Wood anomalies Jean-Fançois Mercier, Simon Felix and Agnès Maurel Institut Langevin, ESPCI, 1 rue Jussieu, Paris-France LAUM, Univ. du Maine, av. O. Messiaen, Le Mans- France Poems, Ensta, bld des Maréchaux, Palaiseau- France jean-francois.mercier@ensta-paristech.fr Abstract Resonant scattering from periodic gratings has been the subject of extensive investigations [1]. The scattering coefficients of any periodic grating are characterized by resonant features, the most remarkable being the manifestations of so-called Wood’s anomalies [2,3]. In recent papers [4,5], studies of the polarization properties in spectral transmittance of a nanohole array grating have been reported. The observations have been interpreted in terms of Fano-type resonnances resulting from the coexistence of the two Wood’s anomalies (in [4], the Fano shape is interpretd in terms of the coherent interference between a discrete and a continuum of states). We present a study based on modal analysis to quantitatively predict the transmission spectrum of an array, accounting for the polarisation (p- or s- polarisations) and on the grating material. It is shown that the equivalent admittance of the grating can be determined in the weak scattering approximation, by integration of a Riccatti type equation governing this admittance. Then, following Oliner and Hessel [3], we propose analytical expressions of the reflexion coefficients for each interference order (of each mode in terms of modal analysis), that account for the shape and for the composition of the grating. Comparison with direct numerical calculations reveals the accuracy of our prediction (Fig. 1). It is shown that the occurence of Fano shape in the reflectance only occurs under certain circumstances, (for s-polarized wave, see Fig. 1, and corresponding electric field on Fig. 2, 3). This is due to the fact that the first Wood anomaly (often referred as the Rayleigh Wood anomaly) always occurs at the cut off frequencies producing the extinction of all the propagative modes while the second -resonant- Wood anomaly does not happen for all gratings (essentially, this is dependent on the wave polarization and on the grating material).

References [1] Focus Issue: “Extraordinary Light Transmission Through Sub-Wavelength Structured Surfaces,” Opt. Express 12, 3618–3706 (2004). [2] R. W. Wood, Phil. Mag. 4, 396 (1902). [3] A. Hessel and A. A. Oliner, Appl. Opt. 4, 1275–1298 (1965). [4] K. Tetz, V. Lomakin, M. P. Nezhad, L. Pang and Y. Fainman, J. Opt. Soc. Am. A 27(4), 911-917 (2010). [5] Z. Cao, H.-Y. Lo, and H.-C. Ong, Optics Lett.. 37(24), 5166-5168 (2012). Figures

0.25

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discrepencies pointed out (we notably consider finite size scatte gratings), we docan notbe have an explanation for this diﬀerence.

kh 0 for this diﬀerence.0 on gratings), we do not have an explanation B/B0 = 0.5 B/B0 0= 2 1 2 0 2π

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H), which is contradictory with the present result. Although

nted out (we

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Fig. 1: Example of reflectance of the mode 0 and mode 2 of a grating with subwavelenght hole arrays ave an explanation for this diﬀerence. kh wave, case of s-polarized (non magnetic kh grating as a function of the frequency of the incident (plane)

|Rpermittivity |R20 | e0/e=0.5). material with denotes the grating period. 20 | 0 e0 smaller 1 than the2host medium, 0 h 00 1 220 2π 2π Plain red lines: full wave calculations, dotted black lines: analytical prediction.

FIG. 7: Reflection coeﬃcient R

= 0.5

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modulus B0 such that 0.5 B/B0 = 0.5 (left), B/B0 = 2 (right).

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0 and R20 for an plane wave 0 0 R00 eflection coeﬃcient impinging at normal incidence 1 2 0 2π 2π 2 01 B. 21Transmission 0 1 2 2π through 2π penetrable/hard grating ade of square scatterers of side a= h/10, emass density ρ0 = ρ, and a Fig. 2:penetrable Same representation for a grating material having a permittivity 0 higher than the host medium (e0/e=2).

|R20 |

In00 this illustration of the multimo R andsection R20 0for planeanwave impinging at normal B0Reflection such that coeﬃcient B/B0 = 0.5 (left), B/B =we2anshow (right). Plain red lines: numerical rei 1

transmission enhancement structures. ck lines:of analytical. made square penetrable scatterers of side athrough = h/10,grating mass density ρ0 =

waves through perforated hard plate were reported recen 0.5 s B0 such that B/B0 = 0.5 (left), B/B0 = 2 (right). Plain red lines: num [38, 39], wekhdescribe the propagation in the layered str kh 0 black analytical. 1 2lines: 0 distribution 1 of the 2 E-field 2π 3: 2πat frequency k=0.998 2p (in norm), just bellow the first cut off Fig. Spatial grating in Dotted terms of the in layered ransmission through penetrable/hard grating (represented on a unit vertical cell). line indicate theclassical position of structures the homogenization grating. Top: in the case of Fig. 1. The scattered field is composed of evanescent modes. The transmission is perfect. Bottom: in the case of Fig. 2. The scattered near field is composed of the grazing mode. The reflexion is perfect.

resulting homogeneous anisotropic medium is method in the  context  section we show an illustration of the multimodal o scatterers of side a = h/10, mass density ρ0 = ρ, and a bulk 1/ρ� 0 ω Transmission  ∇pof+aco ion enhancementthrough through penetrable/hard grating structures. grating transmissions ∇Perfect ·  structures Fig. 4: Spatial distribution of the E-fieldred at frequency 2p (in norm), just above the first cut off B 5 (left), B/B Plain lines:k=1.0001 numerical results, 0 = 2on(right). 1/ρ ⊥ only, (represented a unit vertical cell). The scattered field is composed of the0grazing mode ough perforated plate propagative athard that frequency. Thewere pattern isreported the same in the recently, cases of Figs. 1 see, and 2. e.g., [26, 37, 38].

and R20 for an plane wave impinging at normal incidence on a

his section we show an illustration of the multimodal method in the c

we describe the propagation in the layered structure that forms the perfo 19 ission enhancement through grating structures. Perfect transmission terms of the classical homogenization in layered media. The wave equation i

Opto-electrical characteristics of PEGylated carbon quantum dots I. Mihalache1,2, M. Veca1, M. Kusko1 , A. Radoi1 , E. Vasile3 1.Natl Inst Res & Dev Microtechnol IMT Bucharest, Bucharest 72996, Romania 2.Univ Bucharest, Dept Phys, Bucharest 077125, Romania 3.SC METAV CD, Bucharest, Romania Email: julia.mihalache@gmail.com Abstract Carbon quantum dots, the last member of carbon nanomaterials, owing to their strong and nonbleaching photoluminescence combined with low toxicity and easy conjugation, are acknowledged to be viable counter candidates of semiconducting quantum dots for biology and medicine applications. In order to assess the potential contribution of these materials to other fields than biology, throughout this article we have investigated the optical and electric behavior of two types of PEGylated carbon quantum dots. The article will present both the synthetic routes and photophysical properties, in addition to the electrical measurements achieved on metallic interdigitated electrodes. The material we have investigated, namely carbon quantum dots, were prepared by (i) laser ablation of graphite and subsequently passivation with diamine-terminated oligomeric polyethylene glycol (PEG1500N), denoted CQD-PEG1500N [1] and (ii) microwave assisted hydrothermal method having as precursor glucose based water solution [2] and subsequently passivation with poly(ethylene glycol) bis (carboxymethyl) ether (PEG600), denoted CQD-PEG600. Photophysical characterisations revealed low photoluminescence of self passivated CQD (carbon quantum dots obtained by microwave assisted hydrothermal decomposition of glucose) due to the quenching effect of oxygen rich functional moieties on their surface (epoxy, hydroxyl, and carboxylic groups), but the photoluminescence has greatly increased after polymer passivation (for instance the QY of CQD-PEG1500N is 5% at 440 nm excitation while the photoluminescence of the CQD before passivation is undetectable). Structural studies revealed a size distribution ranging from 2 to 6 nm for the CQD-PEG1500N and 3-4 nm for CQD-PEG600. In addition, HR - TEM characterization confirmed the crystalline structure of the CQD core in all of the carbogenic nanomaterials synthesized in this study, a representative TEM image of CQD-PEG1500N is shown in Fig.1. Photoluminescence (PL) dependence on excitation wavelength in this carbogenic nanomaterial dispersed in chloroform is presented in Fig.2 and is a result of its heterogeneous electronic structure present in the sp2 domains. While the maximum intensity of self passivated CQD and CQD-PEG600 was observed at 380 nm, the CQD-PEG1500N exhibited the highest photoluminescence at 420 nm. Based on those photoluminescence maxima, the optical band gap (Eg opt) of self passivated CQD, CQD-PEG600, and CQD-PEG1500N were calculated to be 2.55 eV, 2.61 eV, and 2.5 eV, respectively. The blue shift smaller than 5 nm is observed in PL of CQD-PEG1500N below 400 nm excitation, which is probably controlled by the size and crystalline structure of the sp2 carbon core and becomes more significant at longer excitation wavelength when effects from surface passivation are dominating.[3] Moreover, CQD-PEG600 shows broader PL peaks than CQD-PEG1500N, which is perhaps the effect of lower a passivation degree. The electrochemical analysis revealed that the presence of the polymer had a reduced influence over quantum dots crystallinity, the overall electrode kinetic was a diffusion-controlled process, where LUMO electrons are extracted via an EC reaction. For CQD-PEG600 electrochemical band gap energy (Eg EC= 2.65 eV) was determined to be larger than the optical one and this difference can be explained by the exciton binding energy of conjugated polymers which is believed to be in the range of 0.4-1.0 eV. The HOMO and LUMO levels were -6.25 eV and -3.6 eV, respectively; two other reduction peaks were observed in cyclic voltamograms which can be assigned with two supplementary LUMO levels inside of bandgap at 3.9 eV and 4.35 eV. Dark current-voltage characteristics for PEGylated nanoparticles deposited on interdigitated gold electrodes have been performed. The results showed a reproductible hysteretic behavior, which can be attributed to either mobile diffusion or to the existence of charged trapping states, due to the modification of surface chemistry .

References [1] Y.P. Sun et al. J. Am. Chem. Soc. 128 (2006), 7756 [2]L. Tang et al. ACSNano 6 (2012), 5102 [3] Q. Mei et al. Chem. Commun. 46 (2010), 7319.

Figures. FIG 1. TEM image of carbon quantum dots after passivation with polymers reveals the dimensions and crystalinity of nanoparticles

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Electrochemical Impedance Spectroscopy applied to the optimization of composites based on graphite/epoxy to be used as amperometric sensor Raquel Montes, Jordi Bartrolí, Mireia Baeza and Francisco Céspedes Grup de Sensors i Biosensors, Departament de Química, Unitat de Química Analítica, Facultat de Ciències, Edifici C-Nord, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain Raquel.Montes@uab.cat The mail goal of this study is the use of alternative strategies of characterization, previously used in transducers based on composite electrodes with carbon nanotubes [1], to characterize and optimize the composite composition based on graphite-epoxy. Moreover, in order to complement the electrochemical results, atomic force microscopy (AFM) was used to gain insights on the surface characteristics of graphite composites and, finally, the electroanalytical response of the optimized composites were evaluated by hydrodynamic amperometry. The development of composites based on conductive phase (graphite, carbon nanotubes, etc.), dispersed in a polymeric matrix (epoxy, methacrylate, Teflon, etc.), has led to important advances in the analytical electrochemistry field, particularly in the development of sensors devices. The characterization and optimization of composite based on graphite-epoxy has been widely studied using different strategies based on several techniques as well as percolation curve or chronoamperometry [2]. Up to now, optimized composites used to have a maximum conductivity with the maximum conductive particles loading into the insulating matrix without losing their physical and mechanical properties. However, the optimization of the signal to noise ratio was not considered. In this work, this parameter was optimized by means of the variation of conductive material loading in the insulating matrix and using novel alternative strategies of characterization which demonstrates that if the composite portions are optimized the response of the electrode is improved [1]. These techniques are electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). EIS measurements provides, in an easy way, information about the electron transfer rate, double layer capacitance, contact resistance and resistance of the solution [3, 4]. The electroanalytical properties required by an electrode are high electron transfer rate, the lowest double layer capacitance and ohmic resistance in order to guarantee a high signal/noise ratio, high sensitivity and low detections limits. By this technique it is possible to determine the composite composition that exhibits these electroanalytical properties. These results can also be contrasted with voltammetric measurements. By means of EIS measurements we can obtain different parameters as ohmic resitance (RΩ), charge transfer resistance (Rct) and double-layer capacitance (Cdl). These parameters were obtained by fitting the impedance spectra to an equivalent circuit (Figure 1). This circuit was sufficiently suitable to interpret the RΩ, Rct and Cdl values in terms of interfacial phenomena that occur at the electrochemical cell [2]. In order to achieve the properties required for an electrode with electroanalytical purposes, such as a rapid response time, low limit detection and a high sensitivity, we are looking for low RΩ, Rct and Cdl values. Figure 2A and Figure 2B present the most significant images obtained during the electrode surface study of the composite with 15% and 20% of graphite load. The composite with 20% of graphite loading showed slightly more conductive areas than in the case of the composite with 15% of graphite loading. Moreover, the distance between the conductive microzones was slightly controlled by a decrease or increase of the graphite loading. Working electrodes based on graphite-epoxy composites were fabricated, characterized and hence optimized by means of EIS and CV techniques, as well as hydrodynamic amperometry and AFM. Such optimal graphite loading values allow us to fabricate attractive and robust composite electrodes with very interesting application as amperometric sensors at low electroanalyte concentration.

[1] Olivé-Monllau, R., Esplandiu, M.J., Bartrolí, J., et al., Actua. B- Chem., 146 (2010), 353-360. [2] Ramírez-García, S., Alegret, S., Céspedes, F., Forster, R.J., Anal. Chem, 76 (2004), 503-512. [3] Pacios, M., del Valle, M., Bartrolí, J., et al., J. Electroanal. Chem., 619-620 (2008), 117-124. [4] Espandiu, M.J., Pacios, M., Cyganek, L., et al., Nanotechnology, 20 (2009), 355-502.

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Figure 2. Topographical AFM images with their corresponding conductance mapping (20x20Âľm) for (A) 20% of graphite loading and (B) 15% of graphite loading.

Multifunctional GNP-Epoxy Nanocomposites for Structural Health Monitoring R. Moriche, S. G. Prolongo, M. Sánchez, A. Jiménez-Suárez and A. Ureña Dpt. of Materials Science and Engineering, University Rey Juan Carlos, C/Tulipán s/n, Móstoles (Madrid), Spain rocio.moriche@urjc.es Abstract Graphene is a 2D material that has attracted the interest of many researchers because of its promising 4 properties. Experimental electrical conductivity of non-single layer ranged in the order of ~10 S/m makes it especially interesting for its use as filler of non-conductive polymer matrix nanocomposites [1]. Reaching the named percolation threshold, nanocomposite turns conductor and for the nanoreinforcement configuration, electrical resistivity is sensible to strain [2][3]. Another important point is the multifunctionality of resulting material as thermal, mechanical [4][5] and barrier properties can be enhanced [6]. 2

The high aspect ratio of graphene due to a sp hybridization of C atoms provokes usually a preferential orientation of the sheets that can be avoided by making use of a rotary system during curing process. That way, we are capable of obtain nanocomposites with preferential and random orientation what means anisotropic and isotropic materials depending on the manufacturing process. In this work we propose an overview of mentioned properties for different aspect ratio graphene nanoplatelets (GNPs). Epoxy nanocomposites were processed by mixing GNPs and epoxy monomer by sonication for 45 minutes. After that, mixture was degassed at vacuum under magnetic stirring for 15 minutes at 80 °C. Hardener was then added and the fluid was cured by both of methods at 140 °C for 8 h. Morphology of nanocomposites was analyzed by TEM, FEGSEM and optical microscopy. Judging from microscopy images and XRD spectra at different parallel sections of the sample, we can conclude that with a normal mold, gravity effect produces a stratification and a preferential in-plane orientation in front of a randomly one in the case of making use of the rotary system. Once we know the reinforcement disposition properties were study in order to achieve multifunctionality. An ageing process to evaluate barrier properties was carried out for 17 days in an atmospheric chamber under constant humidity of 85 % at 60 °C. Samples employed were those obtained with a preferential orientation parallel to the exposed major surface with a 0.5 wt% of GNPs. Extractions were done at different ageing times to elucidate possible differences in tendencies. All the nanocomposites were flexural tested following ASTM D790. Results confirmed expected differences depending on the aspect ratio of the GNPs. For nanocomposites reinforced with higher aspect ratio GNPs, water absorption was less than for the rest and for this reason mechanical properties are less deteriorated. Electrical conductivity was measured till reaching percolation threshold. Once percolation threshold was -5 achieved, a monitoring test was taken. Although electrical conductivity (~10 ) is not too high it is enough to monitories materials deformations. Sensibilities to strain of samples with a GNPs content 6, 8 and 10 wt% were calculated and are in the range of 2-3 what means near an order of magnitude greater than that of CNTs. To summarize we can conclude that the natural preferential orientation of graphene sheets can be easily avoided by making use of a rotary system during the curing stage. This implementation results in a final isotropic nanocomposite that can be desirable for determined applications. A real multifunctionality of these nanocomposites has been corroborated by studying some of the potential intrinsic graphene properties. Properties included in the present work are barrier properties through hydrothermal analysis and electrical conductivity combined with a direct application of Structural Health Monitoring.

References [1] T. Kuilla, S. Bhadra, D. Yao, N. H. Kim, S. Bose and J. H. Lee, Progress in Polymer Science, 35 no. 11 (2010) 1350–1375. [2] H. Hosseinzadegan, C. Todd, A. Lal, M. Pandey, M. Levendorf and J. Park, 25th International Conference on Micro Electro Mechanical Systems (MEMS), IEEE (2012) 611–614. [3] L. Gong, R. J. Young, I. a Kinloch, I. Riaz, R. Jalil, and K. S. Novoselov, ACS nano, 6 no. 3 (2012) 2086–2095. [4] S. Chatterjee, J. W. Wang, W. S. Kuo, N. H. Tai, C. Salzmann, W. L. Li, R. Hollertz, F. a. Nüesch and B. T. T. Chu, Chemical Physics Letters, 531 (2012) 6–10. [5] X.-J. Shen, Y. Liu, H.-M. Xiao, Q.-P. Feng, Z.-Z. Yu and S.-Y. Fu, Composites Science and Technology, 72 no. 13 (2012) 1581–1587. [6] O. Starkova, S. Chandrasekaran, L. a. S. a. Prado, F. Tölle, R. Mülhaupt and K. Schulte, Polymer Degradation and Stability, 98 no. 2 (2013) 519–526.

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Wavelet and fractal basis instead plane-wave in ab-initio calculations Nina Muller, Sergey Seriy, and Uriy Kabaldin Education Ministry of Russian Federation, Komsomolsk-on-Amur State Technical University, Lenina 27, Komsomolsk-on-Amur city, 681013, Russia only_nina@mail.ru, gray@knastu.ru, uru.40@mail.ru Abstract The preferred way to solve partial differential equations is to express the solution as a linear combination of so-called basis functions. These basis functions can for instance be plane waves, Gaussians or finite elements (pic.1). Having discretized the differential equation in this way makes it amenable to a numerical solution. In the case of Poisson’s equation one obtains for instance a linear system of equation, in the case of Schrödinger’s equation one obtains an eigenvalue problem. This procedure is usually more stable than other methods which do not involve basis functions, such as finite difference methods. Wavelets are just another basis set which however offers considerable advantages over alternative basis sets and allows us to attack problems not accessible with conventional numerical methods [1]. Gaussians and plane waves are at present the most popular basis sets for density functional electronic structure calculations. Wavelets are a promising new basis set that combines most of the theoretical advantages of these two basis sets (pic. 2). They can form a systematic orthogonal basis set that allows for adaptivity, the basis functions being localized both in real (compact support) and in Fourier space. Using fractal-basis is more effective way for increase quality and speed of calculation than wavelets. References [1] S. Goedecker and O. V. Ivanov, Computers in Physics 12, 548 (1998). Figures

Pic. 1. Using wavelet basis on DFT

Pic. 2. Direct minimization procedure with plane-waves basis (FFT, left) and wavelet basis (FWT, right)

Selective Adhesion Behaviour of Genetically Engineered Peptides for Chemical Force Microscopy and Nanoparticle Capturing M. Munz, C. Minelli, and A.G. Shard Analytical Science Division, National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK martin.munz@npl.co.uk

Abstract Genetically engineered peptides for inorganics (GEPIs) are a promising approach to provide highly selective interactions between surfaces or complex structures and target entities, such as molecules or nanoparticles. Bottom-up construction or patterning of surfaces and interfaces can be achieved by employing selectively binding building blocks [1]. Furthermore, in sensing applications the selectivity towards a particular analyte can be increased by functionalising the sensor surface with selectively binding molecules [2]. Thus GEPIs are versatile building blocks for a range of applications, from tissue engineering, to biosensing, nanomaterials, and water remediation. Atomic force microscopy (AFM) allows for force measurements between a sharp tip and a target surface. Spatial variations in the molecule-surface interaction force can be measured by covalently attaching molecules to the AFM tip and recording force-distance curves over an array of spots on a surface. In the present study, a gold coated AFM tip was functionalised with peptides via the thiol group of their terminal cysteine. Using a sequence from Naik et al. [3], the peptide C-terminal was designed to selectively bind silica. Gold coated AFM cantilevers with a normal spring constant in the range of 10 - 100 pN, as determined via the thermomechanical method, were used to measure the adhesion force between tailor-made peptides and inorganic surfaces. Prior to the AFM measurements, the cleaned cantilevers were dipped into a 1 mM aqueous solution of the peptides. A Cypher AFM system from Asylum Research was employed. All AFM measurements were taken in NaH2PO4 solutions adjusted to pH6 which contained trace amounts of the surfactant Tween20. Typically, force maps were measured over 2 an area of 20x20 microns . Afterwards, the area was scanned in contact mode to image spatial variations in the frictional/lateral force acting between tip and sample surface (lateral force microscopy, LFM) [4]. The substrates for AFM study consisted of thermally oxidised Si chips which were patterned by thermally evaporating Au whilst the surface was partly masked. A metal grid with a pitch size of ~12.7 microns was used as a mask. Evaporation produced periodic square areas of metal on the surface, corresponding to the pattern of the grid (Figure 1a). A map of the adhesion force measured with a tip that had been functionalised with a silica-binding peptide is shown in Figure 1c. Clearly, a lattice can be seen with a lower adhesion force in the square areas and a higher adhesion force in the areas between the squares. The adhesion force is given by the pull-off force of the force-distance curves measured on an array of 32x32 spots. Approximately, the average adhesion force was ~44 pN on Au coated areas and ~100 pN on silica areas. Also the lateral force was found to be increased on silica (Figure 1b). As a proof-of-concept application, the binding of silica nanoparticles from a suspension was demonstrated. Prior to exposure to the suspension, a gold surface was functionalised with silica-binding peptides. Figure 2a shows an SEM micrograph of the surface with 100 nm particles bound to it. Control experiments shown in Figures 2b and 2c confirmed that the binding is selective for silica. In conclusion, it can be stated that the selective binding of tailor-made peptides has been demonstrated by AFM force-distance curve measurements. Also, LFM has shown an increased friction on silica with respect to gold. These findings have been supported by control experiments using alternative tip functionalisations. As a proof-of-concept, the peptides were utilised to selectively bind silica nanoparticles on a gold surface.

References [1] M. Sarikaya et al, Nat. Mater. 2 (2003), p. 577. [2] L. Nicu and T. Leichle, J. Appl. Phys. 104 (2008), p. 111101-1.

[3] R.R. Naik et al, J. Nanosci. Nanotechnol. 2 (2002), p. 95. [4] M. Munz, J. Phys. D: Appl. Phys. 43 (2010), p. 063001-1. [5] The authors are grateful to A.W. Booker for preparation of the test samples and to N.C. Bell for the synthesis of silica nanoparticles. They thank the Technology Strategy Board for co-funding through a Feasibility Study for Responsible Development of Nanoscale Technologies. This work has been funded by the National Measurement System of the UK Department for Business, Innovation and Skills through the Chemical and Biological Metrology Programme.

Figures

Figure 1. Results of AFM measurements using an AFM tip functionalised with silica-binding peptides. (a) Topography image of an array of Au squares on a silica surface. The scan width is 20 microns. (b) Corresponding lateral force image measured when scanning from left to right. (c) Adhesion map of another area of the same surface. The numbers given are in units of pN and are the average values of the marked areas. The pixel resolution of the map is 32x32.

Figure 2. Selective binding of silica nanoparticles. SEM micrographs of a polycrystalline gold surface functionalised with (a) silica-binding peptides and incubated in silica nanoparticle solution; (b) silicabinding peptides and incubated in a silver nanoparticle solution and (c) silver-binding peptides and incubated in a silica nanoparticle solution.

Carbon Nanotubes doped with different noble metal nanoparticles by near – percolation amperometric sensors 1

Jose Muñoz , Julio Bastos-Arrieta , Jordi Bartrolí , Mireia Baeza , Francisco Céspedes , Dmitri N. 2 2 Muraviev and María Muñoz 1

Grup de Sensors i Biosensors, Departament de Química, Unitat d’Analítica, Facultat de Ciències, Edifici C-Nord, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain 2 Grup de Técniques de Separació, Departament de Química, Unitat d’Analítica, Facultat de Ciències, Edifici C-Nord, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain JoseMaria.Munoz@uab.cat Abstract Composite materials based on different forms of carbon as conductive phase, dispersed in polymeric matrix, have led to important advances in the analytical electrochemistry field, particularly in (bio)sensor devices [1]. Nowadays, the increasing interest is focused on conductive composite materials based on carbon nanotubes (CNTs), due to their high accessible surface area and good electrical, thermal and mechanical properties. The main drawback in CNTs composite materials resides in the lack of homogeneity of the different commercial CNTs lots due to different amounts of impurities in the nanotubes, as well as dispersion in their diameter/length and state of aggregation. Nevertheless, the aspect ratio of the nanotubes is one of the main parameters that determine their percolation behaviour and the conductivity of the composites [2]. Accordingly, the low reproducibility in electrochemical response of (bio)sensors which contain CNTs is due to the low homogeneity of raw nanotubes. For this reason, it is important to study how the different physical properties of these raw CNTs affect in electrochemical response of final (bio)sensor developed [3]. Concurrently, the best composite composition in terms of CNTs content was optimized by Percolation Theory [4].

Previous studies demonstrated that CNTs-doped with metal impurities (89% in carbon purity) had the best electrochemical and amperometric response compared with the same CNTs but purified. These results opened the way to selective doping of CNTs with different metal nanoparticles.Consequently, different Metal Nanoparticles (MNPs) with electrochemical activity; such as Au-, Pd-, Ag-, Cu, Pt-MNPs, and were synthesized by the InterMatrix Synthesis methodology (IMS) on the CNTs surface [5], [6]. IMS technique leads to a more favorable distribution of the MNPs on the CNTs, where non evident agglomerates were observed by High Resolution Transmission Electron Microscopy (HRTEM). The electrochemical response was evaluated by Electrical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV). The feasibility of this approach in terms of electroanalytical response was demonstrated by means of the amperometric detection of ascorbic acid in HNO 3/KNO3 solution 0.05 M [7].

References [1] F. Céspedes, E. Martínez-Fàbregas, S. Alegret, Trac – Trends Anal. Chem., 7 (1996) 296 – 304. [2] CA. Martin, et. al., Polymer, 15 (2005) 877 – 886. [3] J. Muñoz, J. Bartrolí, M. Baeza, F. Céspedes, “The way for the customized construction of MWCNT rd (bio)composite electrodes is opened”, in 3 International Conference on Bio-sensing Technology, Barcelona (Spain), May 12-15, 2013. [4] R. Olivé-Monllau, M. J. Bartrolí, J. Bartrolí, M. Baeza, F. Céspedes, Sensors and Actuators B: Chemical, 1 (2010) 353 – 360. [5] P. , and D. N. Muraviev, Chemistry of Materials, 24 (2010) 6616-6623. [6] Bastos-Arrieta, A. Shafir, A. Alonso, M. Muñoz, J. Macanás, and D. N. Muraviev, Catalysis Today, 1 (2012) 207-212. [7] R. Olivé-Monllau, M. Baeza, J. Bartrolí, F. Céspedes, Electroanalysis, 8 (2009) 931 – 938.

Thermal properties of nanotitania - modified polypropylene fibers Alicja Nejman, Małgorzata Cieślak Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, 5/15 Brzezinska Str., 92-103 Lodz, Poland anejman@iw.lodz.pl

Abstract Nanotechnology is an interdisciplinary technology which enables the production of functional and innovative textile materials with a new features without compromising the basic properties of textile product. Oxidising and reducing properties of titanium dioxide (TiO 2) and the ability to receive TiO2 in the nanometric form, cause the dynamic development of its use as photocatalytic modifier [1,2]. Titanium dioxide (TiO2), thanks to its unique properties is used in many areas [3], including the textile industry, e.g. PP fiber matting. Textile materials modified with TiO2 and their application potential are realistic chance of producing a new generation of products for technical applications. This requires the selection of a suitable product, textile structure and the effective conditions of nanomodification. Thanks to the nanotechnology development it is possible to modify fibers surfaces with nano-TiO2 in order to obtain functional photocatalytic fibers for purification systems, e.g. decompositon of VOCs pollutants [4,5]. Functional oriented design of fibers can change other basic properties of the modified fibers, e.g. thermal properties. The aim of presented work was to assess the impact of TiO2 modification on thermal properties of polypropylene fibers. The research of unmodified (PP) and modified polypropylene fibers (PP/T) were conducted. The technique of differential scanning calorimetry (DSC) with the use of the thermal analyzer DSC 204 F1 Phoenix and thermogravimetric analysis (TGA) with the use of the therobalance TG 209 F1 Libra (Netzsch, Germany) were applied. References [1] Han Z., Chang V. W. C., Zhang L., Tse M. T., Tan O. K., Hildemann L. M., Aerosol and Air Quality Research, 12 (2012) 1327; [2] Fujishima, A.X., Zhang, D.A., Surface Science Reports, 63 (2008) 515; [3] Chen X., Mao S. S., Chemical Reviews, 107 (2007) 2891; [4] Zuo G.-M., Cheng Z.-X., Chen H., Li G.-W., Miao T., Journal of Hazardous Materials B, 128 (2006) 158; [5] Cieślak M., Schmidt H., Świercz R., Wąsowicz W., Fibres & Textiles in Eastern Europe, 17 (2009) 59 Acknowledgements The study has been carried out within the Ministry of Science and Higher Education, Poland [grant number N N508 440736] and the part of work was supported by the Key Project – POIG.01.03.01-00004/08 Functional nano- and micro textile materials - NANOMITEX co-financed by the European Union with the financial resources of the European Regional Development Fund and the National Centre for Research and Development within the framework of the Innovative Economy Operational Programme, 2007-2013, Priority 1. Research and development of modern technologies, Activity 1.3. Supporting R&D projects for enterprises undertaken by science establishments, Subactivity 1.3.1. Development projects.

Chiral D-/L-Penicillamine-protected Ag Triangular Nanoplates Synthesized by Substitution Reaction Naoki Nishida, Yasuhiro Kojima and Hideki Tanaka Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan nnishida@kc.chuo-u.ac.jp Abstract Ag triangular nanoplates have attracted much attention due to their unique geometric structures and optical properties. These unique points are known to be complementary to each other since their optical properties are induced by surface plasmon resonances (SPR) that originate from their structure. Meanwhile, studies of nanoscale chirality have attracted much interest because they have potential in a wide variety of areas such as catalytic and optical applications. Recently, we reported the synthesis of Ag triangular nanoplates protected by chiral glutathione molecules [1]. These nanoplates showed characteristic Cotton effects which were induced by SPR of nanoplates. However, we have prepared Ag nanoplate protected by only one of the enantiomeric species. Herein, we examined synthesis of chiral Ag triangular nanoplates protected by a pair of enantiomers. Ag:PVP (polyvinylpyrrolidone) triangular nanoplates were prepared by photoreduction of silver nitrate ethanol solution as described previously [2]. Subsequently, Ag:Pen (D- or L-penicillamine) nanoplates were synthesized by substitution reaction of Ag:PVP nanoplates with Pen molecules: the Ag:PVP dispersion was mixed and stirred with Pen water solution at room temperature and the formed precipitate was redispersed with water. The structures of the products were observed by scanning transmission electron microscopy (STEM). Additionally, the chiroptical properties were analyzed by circular dichroism (CD) spectroscopy. Figure 1a shows a STEM image for Ag:D-Pen nanoplates. The triangular nanoplates are observed in the STEM image. This indicates that triangular shape of nanoplates is not affected by the present substitution process. As shown in Figure 1b, the CD spectra of Ag:Pen nanoplates exhibited intense Cotton effects with a broad distribution above 500 nm and an almost perfect mirror-image relationship. The wavelength for the distribution was completely different from those for the Pen molecules but was similar to those for the characteristic SPR of nanoplates. Furthermore, the mirror image relationship in CD spectra indicates that chiral nanoplates are synthesized by substitution reaction of the chiral Pens. References [1] N. Nishida, Y. Kojima, H. Tanaka, Chem Lett, 41 (2012) 926. [2] H. Murayama, N. Hashimoto, H. Tanaka, Chem. Phys. Lett, 482 (2009) 291. Figures

Figure 1 (a) STEM image for Ag:D-Pen nanoplates. (b) CD spectra for Ag:D-/L-pen nanoplates.

In situ synthesis of short-chain thiols silver nanoparticles (STSNs) for biological purposes: from silver toxicity to tumors treatment. An overview. 1

J.M. Oliva-Montero , Julio M. Ríos , C. Caro , M.J. Sayagués P.J. Merkling , A. P. Zaderenko ,* 1

Department of Physical, Chemical and Natural Systems. Universidad Pablo de Olavide. Carretera de Utrera Km 1, 41013 Seville, Spain. 2 Institute of Materials Science , CSIC-US, Av. Américo Vespucio 49, 41092 Seville, Spain. apzadpar@upo.es Abstract A novel method for the in situ synthesis of many different short-chain thiols functionalized silver nanoparticles that offer a decorated surface with different organic groups, like amine or carboxilic groups, has been developed. These nanoparticles possess suitable biological properties and the ability to bind different types of biomolecules like cytostatics, antibodies or DNA. The optical properties of the localized surface plasmon resonances (LSPRS) of metal nanoparticles, like gold and silver, offer exceptional characteristics for the next era of medicine. Theranostic is the field of emerging technology occupied in the development of new systems for both diagnostic and treatment of several pathologies. These plasmonic nanosystems allow targeted delivery of molecules and their monitoring through different optical imaging techniques. On the other hand, the SERS and SEIRAS effect of these nanosystems may be suitable for biosensing methods in order to determinate the presence of metabolites, proteins, oligonucleotides sequences or pollutants faster and with increased sensitivity compared to that of conventional techniques [1]. The organic capping agents studied were 4,6-Diamino-2-mercaptopyridine, mercaptoacetic acid and cysteamine, being the last one of paramount interest due to its biomedical properties and physicalchemistry skills, as well as its positive charge at physiological pH. These characteristics make cysteamine an exceptional candidate for interaction essays with DNA/RNA sequences.

Many studies relate toxicity of silver nanoparticles with ROS generation and apoptosis via the mitochondrial pathway [2]. The threshold resistance to oxidative stress is higher in healthy cells than it is in tumor cells. Thus, we propose the use of these thiol-functionalized silver nanoparticles as adjuvants in cancer disease and as drug vector systems [3]. We assessed the capability of these nanoparticles for siRNA delivery by conjugating siRNA targeting Bcl-2 protein, implicated in the resistance of many tumors.

References [1] Nikolai G. Khlebtsov et al. Journal of Quantitative Spectroscopy & Radiative Transfer 111 (2010) 1– 35 [2] Yi-Hong Hsin et al. Toxicology Letters. 179 (2008) 130–139 [3] H. Pelicano et al. Drug Resistance Updates 7 (2004) 97-110,

Figures

Transmittance [%]

3500

3000

2500 2000 Wavenumber cm-1

1500

1000

Figure. Cysteamine silver nanoparticles. (A) TEM, (B) size distribution, (C) UV-Vis spectrum, (D) FT-IR spectra, dotted line cysteamine, solid line cysteamine silver nanoparticles.

In situ synthesis of short-chain thiols silver nanoparticles (STSNs) for biological purposes: from silver toxicity to tumors treatment. An overview. 1

J.M. Oliva-Montero , Julio M. Ríos , C. Caro , M.J. Sayagués P.J. Merkling , A. P. Zaderenko ,* 1

Figures

Transmittance [%]

3500

3000

2500 2000 Wavenumber cm-1

1500

1000

Figure. Cysteamine silver nanoparticles. (A) TEM, (B) size distribution, (C) UV-Vis spectrum, (D) FT-IR spectra, dotted line cysteamine, solid line cysteamine silver nanoparticles.

New directions in organic synthesis: silver-catalyzed Sonogashira cross-coupling of chlorobenzene and phenylacetylene Noe Orozco Corrales, Carlos Sanchez Sanchez, Agustin Rodriguez Gonzalez-Elipe, Lety Feria, Javier Fernandez Sanz and Richard M. Lambert Instituto de Ciencias de Materiales de Sevilla (CSIC), C/ AmĂŠrico Vespucio 49, Sevilla, Spain noe.orozco@icmse.csic.es

Abstract Metal-catalyzed Sonogashira coupling reactions that lead to the formation of new C-C bonds are of strategic importance in synthetic organic chemistry [1]. They provide a powerful and flexible method for systematically and efficiently constructing complex molecular architectures from suitably tailored building blocks. This chemistry is almost always carried out homogeneously using expensive organometallic complexes of palladium as catalysts. It is now the most important method for preparing arylalkynes and conjugated enynes, which are key precursors in the synthesis of natural products, pharmaceuticals, and molecular organic materials. The ability to carry out such reactions heterogeneously by means of suitable low cost nanoparticle catalysis is a highly desirable goal because of the well-known operational advantages of heterogeneous over homogeneous methodology. Moreover, the availability of inexpensive and air-stable nanoparticle catalysts capable of carrying out Sonogashira coupling with low-cost aryl chlorides (as opposed to expensive aryl iodides) would greatly expand the possibilities for scale-up and technological implementation of Sonogashira coupling [2] Here, by means of single crystal experiments involving STM and temperature programmed reaction (TPR) supported by DFT calculations, we show that the Ag(100) surface catalyzes Sonogashira . coupling of chlorobenzene (ClBz) and phenyl acetylene (PA), thus meeting both the above stated objectives. It is found that both reactants show a pronounced tendency to form islands on extended terraces, thus inhibiting cross-coupling activity which is thought to occur where island boundaries are proximate (Figure 1A and B). Consistent with this view, deliberately roughening the surface so as to limit island size results in the onset of Sonogashira coupling. In this way, simultaneous co-adsorption of PA and ClBz from an approximately equimolar vapour under UHV conditions followed by TPR measurements showed that homocoupling of PA to diphenyldiacetylene (DPDA) and of Chlorobenzene to biphenyl (BP) occurred. Most importantly, Sonogashira cross coupling of the two reactants to yield diphenylacetylene (DPA) was also observed (Figure 1C). These findings open the door to the design and development of optimized Ag nanoparticle catalyst systems.

References [1] Rafael Chinchilla and Carmen Najera, Chemical Reviews, Vol. 107 Issue 3 (2007) 874. [2] Robin B. Bedford, Catherine S.J. Cazin, Debbie Holder, Coordination Chemistry Reviews, 248 (2004) 2283.

Figures

Figure 1.- A. STM image of PA structures on clean Ag(100) surface after annealing at 200K for 10 minutes. T = 115K, (15nm x 15nm) I = 0.40nA, V = 2.3V. B. STM image of ClBz hexagonal structure obtained after annealing at 240K for 10 minutes. T = 115K, (25nm x 25nm) I = 0.44nA, V = 1.9V. C. TPR spectra for the reaction products obtained after co-adsorption of ClBz and PA.

CARBON NANOSCROLLS FABRICATION BY A MICROMECHANICAL TECHNIQUE

M. Palomba , V. Romeo , G. Carotenuto , L. Ambrosio , L. Nicolais

Institute for Composite and Biomedical Materials of National Research Council of Italy (IMCB-CNR), Mostra d'Oltremare pad. 20, Viale J.F. Kennedy 54, 80125 Napoli.Italy. 2 Department of Chemical Science and Materials Technology of National Research Council of Italy (DSCTMCNR), Via dei Taurini, 19, 00185 Roma, Italy. 3 Department of Chemical, Materials and Production Engineering, University “Federico II” of Naples, P.le Tecchio, 80 , 80125 Naples, Italy. marianopalomba@fastwebnet.it

A simple micromechanical approach (that is, the peeling off) has allowed to extract graphene molecules from a graphite crystal [1]. During the peeling out of the graphite crystal, the applied mechanical stress causes the separation of the graphene layers, contrasting the interlayer interaction forces. Analogously a particular mechanical stress (shear stress) can allow the graphite nanocrystals (graphite nanoplatelets, GNPs) to transform into a new carbon nanomaterial, which is the carbon nanoscroll (CNS). In this case, the applied stress acts on the single carbon sheet, moving and causing a complete graphite crystal exfoliation. However, when this movement of the graphene sheets takes place against a rough surface it causes a rolling-up process because of the effect of the acting friction forces. In particular, when the micromechanical exfoliation takes place against a nano-fibrous surface like bioriented polypropylene (BOPP) this scrolling mechanism results particularly favored. In this study, an alcoholic (ethanol) dispersion of (Few Layer Graphene, FLG) was rubbed on the surface of a bioriented polypropylene (BOPP) film using a low-density polytethylene (LDPE) film. Before to dry the concentrated liquid suspension was removed from the BOPP film by pouring ethanol on it. The resulting dispersion contained a large amount of nanoscrolls. Probably the high roughness and nano-fibrous nature of the BOPP surface helps the rolling process. Nanoscrolls can be separated from the un-rolled and/or partially rolled graphene-based material by sedimentation in ethanol since their Stokes coefficient value is significantly higher than that of graphene. The ability of the shear-stress forces to induce nanoscroll formation has already been observed in the treatment of graphite by ball milling. Carbon nanoscrolls are made of continuous graphene sheets rolled up in a hollow tubular form. They are materials analogous to multi-walled carbon nanotubes, and therefore can be considered as nanotube-like structures. Moreover, there are different ways for the graphene unities to separate from the graphite crystal during the rolling-up process under the effect of the applied shear stress. Cylindrical and fusiform structures typically result in addition to partially rolled, multi-rolled, and other non-regularly-shaped rolled structures. Cylindrical nanoscrolls have a very uniform diameters and tend to form bundles just like carbon nanotubes (CNT) because of the π-π interactions. The average length of cylindrical nanoscrolls obtained by this method was ranging from 0.5 to 2.5 μm, and the diameter was of ca. 100nm. Consequently, each cylindrical nanoscroll should contain from 2 to 8 inner layers (n=l/πD). Nanoscrolls containing only a few graphene layers result quite transparent (see the TEM - SEM micrographs in Figure 1,2). However, for fusiform nanoscrolls the number of layers resulted of ca. 11 in the equatorial region (n=l√2/πD). These nanostructures are hollow and therefore particularly useful for many technological applications like hydrogen storage [3-4], drug-delivery systems, etc. Carbon nanoscrolls offer a number of advantages compared to planar graphene. Graphene 2 has a large surface development (2630 m /g) but also a certain tendency to aggregate by stacking. Such problem is completely solved in carbon nanoscrolls that may only moderately aggregate. Owing to the very high specific surface area, carbon nanoscrolls can have important application as sorbents and catalyst supports, in addition they are electrically conductive and therefore can be used in the fabrication of electrodes for supercapacitors and batteries [2], where high current densities are required. In addition, these nanostructures are characterized by a temperature-dependent rolling level, and therefore the release by diffusion of molecules contained inside the nanoscroll could behave differently, depending on the temperature. Also a temperature-depending electrical conduction has been observed for carbon nanoscrolls that allow their use as temperature sensors. The interlayer spaces of CNS can be easy intercalated because it is not a closed topological structure. Since the diameter of CNS can be easily expanded by charge injection or intercalation, it could also be used as a nanoactuator in nanomechanical devices [2-5].

References [1] A. K. Geim, Science, 324 (2009) 1530. [2] S. F. Braga, V. R. Coluci, S. B. Legoas, R. Giro, D. S. Galvao, R. H. Baughman, Nano Lett., 4 (2004) 881. [3] G. Mpourmpakis, E. Tylianakis, G. E. Froudakis, Nano Lett., 7 (2007) 1893. [4] V. R. Coluci, S. F. Braga, R. H. Baughman, D. S. Galvao, Phys. ReV. B, 75 (2007) 125404. [5] R. Rurali, V. R. Coluci, D. S. Galvao, Phys. ReV. B, 74 (2006) 085414. Figures

Figure 1: (left side) SEM micrograph of a bundle of scrolled material; (right side) high magnification SEM image of some tubular nanoscrolls.

Figure 2: (left side) TEM image of nanoscrolls produced by the mechanical stress ; (right side) TEM image of an isolated carbon nanoscroll.

Graphene oxide related forms for biosensing applications L. Baptista-Pires, B. Pérez-López, Carmen C. Mayorga-Martinez, Eden Morales-Narváez , Neus Domingo , Maria Jose Esplandiu , Francesc Alzina , C. M. Sotomayor Torres and A. Merkoçi

Nanobioelectronics & Biosensors Group, Catalan Institute of Nanoscience and Nanotechnology, CIN2 (ICN-CSIC) Campus de la UAB, 08193 Bellaterra, Barcelona, Spain Luispires.icn@gmail.com Abstract 1

Since the discovery of graphene in the last years and with the great progress made in nanoscience and nanotechnology, its integration with biomolecules has received increased attention due to its physical, optical and chemical properties which are not available in other materials, such as its interesting molecular structure, high surface area and high conductivity capacity that improves the electron 2

transfer . Since then, many graphene materials such as graphene oxide

3,4

, graphene quantum dots or

graphene nanoribbons have been reported . Graphene oxide with different oxidized grades, exhibits different defects levels due to the distribution of the oxygen atoms all over the graphene surface. Epoxy and hydroxyl groups lie above and below each 7

graphene layer and the carboxylic groups are mostly located at the edges . The presence of the oxygen groups onto the surface of the graphene sheet results in a highly hydrophilic character, which strongly affects the density of electronic states (DOS) and consequently the chemical reactivity and 8

conductivity tuning its properties either to insulator or semimetallic . The presence of epoxy and hydroxyl groups (within holes or not) in the basal plane and the flexibility of the oxidized graphene sheet can determine the preferential binding of enzymes. Instead, the edges which result to be hydrophobic 9

interactuators reduce the capability for binding sites . The versatility of oxidative grades of graphene leads to transitions from insulator to semimetallic mainly after reducing processes 11

or bacterial treatment

. Reduction modes such as reduction using hydrazine and thermal annealing

which resulted in highly reasonable methods for the reconstruction of the

graphene oxide sheet have been developed. The reduction of graphene oxide removes the oxygen 3

groups and rehybridize the sp carbon atoms to sp carbon atoms

According to their properties, the graphene oxide opens the door for biofuncionalization with enzymes, DNA, antibodies, between other biomolecules. Therefore, due to the biofunctionalization capabilities 2

combined with interesting electrochemical and optical properties

graphene oxide has greatly

stimulated research interest for applications in (bio)sensing systems. The use of graphene-based

biosystems improves the detection levels , being a great promise for routine sensitive, selective, rapid, and cost-effective analysis making them suitable for environmental, food safety and security and medical applications. This work presents a detailed characterization of oxidized graphene oxide (oGO) and reduced graphene oxide (rGO) sheets on screen-printing electrodes, one of the most interesting platforms for electrochemical biosensors. The electrochemical response is sensitively followed by using catechol as a proof of concept analyte. For this study we have used highly oxidized graphene oxide (oGO) which have 4

been reduced afterwards with hydrazine for de-oxygenation of oGO. The electrochemical responses of this reduced graphene oxide (rGO) have been compared with the responses obtained for oGO and their performance has been accordingly discussed with various evidences obtained by optical techniques.

References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

12. 13. 14. 15.

Geim, A. K. & Novoselov, K. S. The rise of graphene. Nat. Mater. 6, 183-191, doi:10.1038/nmat1849 (2007). Shao, Y. Y. et al. Graphene Based Electrochemical Sensors and Biosensors: A Review. Electroanalysis 22, 1027-1036, doi:10.1002/elan.200900571 (2010). Shen, J. F. et al. Fast and Facile Preparation of Graphene Oxide and Reduced Graphene Oxide Nanoplatelets. Chem. Mat. 21, 3514-3520, doi:10.1021/cm901247t (2009). Marcano, D. C. et al. Improved Synthesis of Graphene Oxide. ACS Nano 4, 4806-4814, doi:10.1021/nn1006368 (2010). Peng, J. et al. Graphene Quantum Dots Derived from Carbon Fibers. Nano Lett. 12, 844-849, doi:10.1021/nl2038979 (2012). Martin-Fernandez, I., Wang, D. B. & Zhang, Y. G. Direct Growth of Graphene Nanoribbons for Large-Scale Device Fabrication. Nano Lett. 12, 6175-6179, doi:10.1021/nl302993m (2012). Zhu, Y. W. et al. Graphene and Graphene Oxide: Synthesis, Properties, and Applications. Adv. Mater. 22, 3906-3924, doi:10.1002/adma.201001068 (2010). Eda, G., Mattevi, C., Yamaguchi, H., Kim, H. & Chhowalla, M. Insulator to Semimetal Transition in Graphene Oxide. J. Phys. Chem. C 113, 15768-15771, doi:10.1021/jp9051402 (2009). Kotchey, G. P. et al. The Enzymatic Oxidation of Graphene Oxide. ACS Nano 5, 2098-2108, doi:10.1021/nn103265h (2011). Mathkar, A. et al. Controlled, Stepwise Reduction and Band Gap Manipulation of Graphene Oxide. J. Phys. Chem. Lett. 3, 986-991, doi:10.1021/jz300096t (2012). Gao, X. F., Jang, J. & Nagase, S. Hydrazine and Thermal Reduction of Graphene Oxide: Reaction Mechanisms, Product Structures, and Reaction Design. J. Phys. Chem. C 114, 832842, doi:10.1021/jp909284g (2010). Salas, E. C., Sun, Z. Z., Luttge, A. & Tour, J. M. Reduction of Graphene Oxide via Bacterial Respiration. ACS Nano 4, 4852-4856, doi:10.1021/nn101081t (2010). Cheng, M. et al. Restoration of graphene from graphene oxide by defect repair. Carbon 50, 2581-2587, doi:10.1016/j.carbon.2012.02.016 (2012). Morales-Narvaez, E. & Merkoci, A. Graphene Oxide as an Optical Biosensing Platform. Adv. Mater. 24, 3298-3308, doi:10.1002/adma.201200373 (2012). Wang, Y., Wan, Y. & Zhang, D. Reduced graphene sheets modified glassy carbon electrode for electrocatalytic oxidation of hydrazine in alkaline media. Electrochem. Commun. 12, 187-190, doi:10.1016/j.elecom.2009.11.019 (2010).

Figure

Figure 1. Schematic diagram (not in scale) displaying the enzyme (Tyrosinase) and reactions involved in the catechol detection at the SPE modified with oGO (a) and rGO (b).

Optimization of Spray-Coated MWCNTs Based Working Microelectrodes for Electrochemical sensors 1,2

1,2

Jan Prasek , Petra Majzlikova , Filip Lechner , Jana Chomoucka , Jana Drbohlavova , Jan 1,2 1,2 1,2 Pekarek , Radim Hrdy and Jaromir Hubalek 1

Department of Microelectronics, Brno University of Technology, Technicka 3058/10, Brno, Czech Republic 2 Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, Brno, Czech Republic prasek@feec.vutbr.cz Abstract Easy, fast and reliable detection of species in environment under field conditions or in vitro/vivo online biodetection is one of the most discussed problems in these days. In general, small handheld, usually electrochemical, systems using miniaturized sensors are therefore developed [1, 2]. The main problem of electrochemical sensors miniaturization is reduction of their geometrical size in comparison to standard electrodes resulting in lower current response. This problem could be solved by creation of some 3D structures on the geometrically reduced electrode which could increase the active size of the electrode several times. Such electrode system could be used as a base for high sensitive intelligent sensors and biosensors [3]. Carbon nanotubes (CNTs) have been under scientific investigation more than fifteen years. Their unique properties predestine them for numerous potential applications including the working electrodes of electrochemical sensors [4-6]. Moreover the suspension made of CNTs with suitable vehicle can form the porous working electrode of high electrochemically active surface. In this work the standalone multiwalled carbon nanotubes (MWCNTs) based spray-coated working electrodes of electrochemical sensors were optimized with respect to the accurate electrochemical behavior of deposited layers. Two types of thick-film platinum electrode contacts were investigated (Figure 1 left) and the suitable thickness of spray-deposited MWCNTs/DMF active layers was studied. Fabricated electrodes (Figure 1 right) were characterized optically using scanning electron microscopy and electrochemically in a standard redox couple of potassium ferro/ferricyanide employing cyclic voltammetry and impedance spectroscopy. The reversibility of the electrode system, influence of spray-coated layer thickness and platinum electrode contact size on the current response were investigated. From the SEM images of fabricated Pt(+) contact/Al2O3 substrate crossing shown in figure 2 (left and middle) is clear that 1 ml of spray-coated suspension leave visible step between contact and the substrate, which almost disappear with 5 ml of spray-coated suspension. Other images of active layer taken on Pt contact and pure alumina substrate (Figure 2 right) confirmed worse coverage of alumina substrate by electrode material. This fact leaded to loosing of active layer adhesion during the measurement and thus the destruction of the electrode. This problem was observed namely on small Pt(mk) contact. The electrochemical cyclic voltammograms of electrodes with small Pt(mk) contact and large Pt(+) contact are shown in the figure 3. From the figure 3 is clear that large Pt(+) contact gives more stable and accurate response which is probably given by better adhesion of MWCNTs active layer to platinum and better current propagation from the CNTs to the electrical circuit. This fact was also confirmed by electrochemical impedance spectroscopy. Next experiments also confirmed, that more stable and repeatable behavior was achieved using the electrodes with bigger platinum contact and lower thickness of deposited active layers. References [1] Li Z, Zeng G M, Tang L, et al., Biochemical Engineering Journal, 3 (2011) 185-192. [2] Mulazimoglu I E, Energy Education Science and Technology Part a-Energy Science and Research, 1 (2011) 393-400. [3] Fujcik L, Prokop R, Prasek J, et al., Microelectronics International, 1 (2010) 3-10. [4] Cai X J, Gao X, Wang L S, et al., Sensors and Actuators B-Chemical, (2013) 575-583. [5] Hussain S T, Abbas S M, Bangash M A K, et al., Journal of the Chemical Society of Pakistan, 3 (2013) 604-610. [6] Prasek J, Hubalek J, Adamek M, et al., IEEE Sensors, (2006), 1253-1256.

Figures

Figure 1. Two types of thick-film contacts design (left) and fabricated electrode (right)

Figure 2. SEM microimages Pt(+) contact/Al2O3 substrate crossing covered with 1 ml of spray-coated MWCNTs/DMF active layer (left) and 5 ml (middle). The image of deposited active layer on the alumina substrate (right).

Figure 3. Cyclic voltammograms recorded at 50 mV/sec in 2.5 mM potassium ferro/ferricyanide solution for different active layer thickness achieved at small contact Pt(mk) (left) and large contact Pt(+) (right). Acknowledgment This work has been supported by Grant Agency of the Czech Republic under the contract GACR P205/10/1374, the operational program Research and Development for Innovation, by the project â&#x20AC;&#x153;CEITEC - Central European Institute of Technologyâ&#x20AC;? CZ.1.05/1.1.00/02.0068 from European Regional Development Fund and by the project Research4Industry CZ.1.07/2.4.00/17.0006 from European Social Fund.

Giant Magnetoresistance with Temperature-dependent Crossover in FeNi3-graphene Nanocomposites H. Prima-García ,G. Abellán, E. Coronado Instituto de Ciencia Molecular (ICMol), Universidad de Valencia. Catedrático José Beltrán 2, 46890 Paterna, Spain. Fax: +34 96 354 3273. Telf: +34 96 354 4419. E-mail: helena.prima@uv.es A dramatic temperature-dependent crossover from positive room-temperature Giant Magnetoresistance (GMR) to negative Low-field Tunneling Magnetoresistance (LFTMR) below 50 K is observed in FeNi3-graphene nanocomposites. Two clearly different behaviors have been discovered, being the temperature barrier ca. 50 K. The low-temperature behavior is particularly sensitive to low magnetic fields. The nanocomposites where synthesized by means thermal decomposition of a hybrid sebacate-intercalated layered double hydroxides as single source precursor. The as-synthesized nanocomposites consist on ferromagnetic FeNi3 nanoparticles embedded in a few-layers graphene matrix. This work represents a straightforward methodology based on chemical synthesis for the preparation of magnetoresistance materials offering great possibilities as GMR sensors. All of our data suggest that we have a ferromagnetic nanoparticles/carbon matrix nanocomposite whose matrix conductivity can be tuned with temperature, thus offering the possibility of modulate the MR behavior. Moreover, all the rich MR phenomenology occurs under low fields. Our GMR granular nanocomposites can operate at room temperature or low fields in contrats to multilayered GMR materials, where a high magnetic field is required to saturate the MR, suggesting promising applications as GMR sensor References

[1] Federico García Lorca, Gypsy Ballads, (1928) [2] Washington Irving, Tales of the Alhambra, (Carey&Lea, USA, 1832), Chap. 1.1

Figure 1: Magneto-Resistance for 900ºC nanocomposite, and the zoom of the Low magnetic field range.

Electron localization in semiconductor nanostructures: from quantum to classical correlations A. Puente, M. Pons Universitat de les Illes Balears, Departament de FĂsica, E-07122 Palma de Mallorca, Spain toni.puente@uib.es Abstract The properties of electronic ground state wave functions in semiconductor nanostructures under the influence of a magnetic field, has been the subject of many theoretical efforts in the last decades. Many finite system studies have been carried out [1] providing also useful insight into the behavior of the 2d electron gas at different filling factors, and in particular in the fractional quantum Hall regime. Several theoretical descriptions have been proposed, differing mainly in the way correlations are included and how symmetries are dealt with in the wave functions. Starting from the seminal paper by Laughlin [2], these include composite-fermion methods [3], pinned Hartree-Fock Wigner crystals [4] or the quantal theory of roto-vibrational electron molecules [5] for finite systems. In this work we analyze the infinite magnetic field limit as a source of electron localization by using simple pinned Wigner crystal wave functions. Supported by exact solutions for N=2 and N=3 [6] electrons at very high magnetic fields, we explicitly show that the interplay of confinement and electronic interaction, essential to describe fractional filling factor states, can be dealt with in a perturbative way for any number of electrons. The role of different shape isomers and their effect on quantum dot addition energies at high magnetic fields will be discussed. References [1] for a recent review see: C. Yannouleas, U. Landman, Rep. Prog. Phys., 70 (2007) 2067. [2] R. B. Laughlin, Phys. Rev. Lett., 50 (1983) 1395. [3] C.-C. Chang, G. S.Jeon, J. K. Jain, Phys. Rev. Lett., 94 (2005) 016809; C.-C. Chang, C. TĂśke, G. S.Jeon, J. K. Jain, Phys. Rev. B, 73 (2006) 155323. [4] H. Fukuyama, P. A. Lee, Phys. Rev. B, 18 (1978) 6245; K. Maki, X. Zotos, Phys. Rev. B, 28 (1983) 4349. [5] C. Yannouleas, U. Landman, Phys. Rev. A, 81 (2010) 023609; Constantine Yannouleas, Uzi Landman, Phys. Rev. B, 84 (2011) 165327. [6] M Taut, J. Phys.: Condens. Matter, 21 (2009) 075302; M Taut, J. Phys.: Condens. Matter, 12 (2000) 3689.

Photovoltaic LiNbO3 particles: Applications to Biomedicine/Biophotonics B. J. Ramiro2, A. Blázquez-Castro1, A. García-Cabañes1, L. Arizmendi1, A. Méndez2, A. Alcázar2, J. C. Stockert3, F. Agulló-López1,4, and M. Carrascosa1 1

Depto. de Física de Materiales, Universidad Autónoma de Madrid, 28049 Madrid, Spain 2 Depto. Aerotecnia, Universidad Politécnica de Madrid, 28040 Madrid, Spain 3 Depto. de Biología, Universidad Autónoma de Madrid, 28049 Madrid, Spain 4 CMAM, Universidad Autónoma de Madrid, 28049 Madrid, Spain

j.ramiro@upm.es Abstract Recently, a novel method to trap and pattern ensembles of nanoparticles has been proposed and tested. It relies on the photovoltaic (PV) properties of certain ferroelectric crystals such as LiNbO 3 [1,2]. These crystals, when suitably doped, develop very high electric fields in response to illumination with light of suitable wavelength. The PV effect lies in the asymmetrical excitation of electrons giving rise to PV currents and associated space-charge fields (photorefractive effect). The field generated in the bulk of the sample propagates to the surrounding medium as evanescent fields. When dielectric or metal nanoparticles are deposited on the surface of the sample the evanescent fields give rise to either electrophoretic or dielectrophoretic forces, depending on the charge state of the particles, that induce the trapping and patterning effects [3,4]. The purpose of this work has been to explore the effects of such PV fields in the biology and biomedical areas. A first work was able to show the necrotic effects induced by such fields on He-La tumour cells grown on the surface of an illuminated iron-doped LiNbO 3 crystal [5]. In principle, it is conceived that LiNbO3 nanoparticles may be advantageously used for such biomedical purposes considering the possibility of such nanoparticles being incorporated into the cells. Previous experiments using microparticles have been performed [5] with similar results to those achieved with the substrate. Therefore, the purpose of this work has been to fabricate and characterize the LiNbO 3 nanoparticles and assess their necrotic effects when they are incorporated on a culture of tumour cells. Two different preparation methods have been used: 1) mechanical grinding from crystals, and 2) bottom-up sol-gel chemical synthesis from metal-ethoxide precursors. This later method leads to a more uniform size distribution of smaller particles (down to around 50 nm). Fig. 1(a) and 1(b) shows SEM images of the nanoparticles obtained with both method. An ad hoc software taking into account the physical properties of the crystal, particullarly donor and aceptor concentrations has been developped in order to estimate the electric field generated in noparticles. In a first stage simulations of the electric current of nanoparticles, in a conductive media, due to the PV effect have been carried out by MonteCarlo simulations using the Kutharev 1-centre transport model equations [6] . Special attention has been paid to the dependence on particle size and [Fe2+]/[Fe3+]. First results on cubic particles shows large dispersion for small sizes due to the random number of donors and its effective concentration (Fig 2). The necrotic (toxicity) effect of nanoparticles incorporated into a tumour cell culture subjected to 30 min. illumination with a blue LED is shown in Fig.3. For each type of nanoparticle the percent of cell survival in dark and illumination conditions has been plot as a function of the particle dilution factor. Fig. 1a corresponds to mechanical grinding particles whereas 1b and 1c refer to chemically synthesized particles with two oxidation states. The light effect is larger with mechanical grinding nanoparticles, but dark toxicity is also higher. For chemically synthesized nanoparticles dark toxicity is low but only in oxidized samples, where the PV effect is known to be larger, the light effect is appreciable. These preliminary results demonstrate that Fe:LiNbO· nanoparticles have a biological damaging effect on cells, although there are many points that should be clarified and much space for PV nanoparticles optimization. In particular, it appears necessary to determine the fraction of nanoparticles that become incorporated into the cells and the possible existence of threshold size effects. This work has been supported by MINECO under grant MAT2011-28379-C03. References

[1] H. A. Eggert, F. Y. Kuhnert, K. Buse, J. R. Adleman and D. Psaltis, Appl. Phys. Lett., 90 (2007) 241909. [2] J. Villarroel, H. Burgos, A. Garc鱈a-Caba単es, M. Carrascosa, A. Blazquez-Castro ad F. Agullo-Rueda, Opt. Express, 19 (2011) 24321. [3] X. Zhang, J. Wang, B. Tang, X.Tan, R. A. Rupp, L. Pan, Y. Kong, Q. Sun and J. Xu, Opt. Express, 17 (2009) 9981. [4] H. Burgos, M. Jubera, J. Villarroel, A. Garcia-Caba単es, F. Agullo-Lopez and M. Carrascosa, Opt. Mat. 35 (2013) 1700. [5] A. Blazquez-Castro, J. C. Stockert, B. Lopez-Arias, A. Juarranz, F. Agullo-Lopez, A. Garcia-Caba単es and M. Carrascosa, Photochem. Photobiol. Sci., 10 (2011) 956. [6] Kuktharev N.V., Markov V.B., Odulov S.G., Soskin M.S., Vinetskii V.L., Ferroelectrics 22, 949 (1979). Figures

(a)

(b)

Figure 1.- SEM imagines of LiNbO3:Fe nanoparticles obtained by: (a) mechanical grinding, (b) chemical synthesis.

Figure 2.- Current density as a function of particle size. Dots represent individual particles. Lines connect mean current density for each size.

(a)

(b)

(c)

Figure 3.- Percent cell survival versus nano-particles concentration in solution obtained by mechanical grinding (a) and obtained by chemical synthesis and oxidized (b) and reduced (c) by thermal treatments.

Ionic Liquid Mediated Synthesis and Surface Modification of Multifunctional Mesoporous Eu:GdF3 Nanoparticles for Biomedical Applications Sonia Rodriguez-Liviano, Instituto de Ciencia de Materiales de Sevilla (CSIC-US), Americo Vespucio 49, Isla de La Cartuja, 41092 Sevilla, Spain Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Mariano Esquillor s/n, Zaragoza, 50018, Zaragoza, Spain sonia.rodriguez@icmse.csic.es Abstract A procedure for the synthesis of multifunctional europium(III)-doped gadolinium(III) fluoride (Eu:GdF3) nanoparticles (~85 nm) with quasispherical shape (Fig. 1, left) by precipitation at 120 °C from diethylene glycol solutions containing lanthanide chlorides and an ionic liquid (1-Butyl, 2- methylimidazolium tetrafluoroborate) as fluoride source has been developed [1]. These nanoparticles were polycrystalline and crystallized into a hexagonal structure, which is unusual for GdF 3. They were also mesoporous 2 −1 (pore size = 3.5 Å), having a rather high BET surface area (75 m g ). The luminescent (Fig. 1, right) and magnetic (relaxivity) (Fig. 2) properties of the Eu:GdF3 nanoparticles have been also evaluated in order to assess their potentiality as “in vitro” optical biolabels and contrast agent for magnetic resonance imaging. Finally, a procedure for their functionalization with aspartic-dextran polymers is also reported. The functionalized Eu:GdF3 nanoparticles presented negligible toxicity for Vero cells (Fig. 3), which make them suitable for biotecnological applications.

References [1] S. Rodriguez-Liviano, N. O. Nuñez, S. Rivera, J. M. de la Fuente, and M. Langmuir, 29 (2013), 3411-3418

Figures

Figure 1 – Left: TEM image of the nanoparticles prepared by heating at 120 °C for 15 h, DEG solutions −3 −3 containing 0.019 mol dm of GdCl3, 0.001 mol dm of EuCl3 [Eu/(Eu + Gd) mol ratio = 0.05], and 40% by volume of BMIMBF4. Right: Photograph taken under UV illumination for the Eu0.05Gd0.95F3 nanophosphor in water suspension.

Figure 2 –Proton relaxivities (r1 and r2) measured for the Eu:GdF3 nanophosphor at 1.5 T.

Figure 3 – Cytotoxicity profiles of functionalized nanoparticles with Vero cells, as determined by MTT assay. Percentage of viability of cells was expressed relative to control cells (n = 5). Results are represented as mean ± standard deviations.

n::CAD a novel suit for nanotecnology Presenting Guillermo Romรกn, Paul Bartholomeus Sgenia, Calle Chile, nยบ 4, 28230 Las Rozas de Madrid, Spain pbartholomeus@sgenia.com Abstract n:: CAD is conceived as a new tool for the design, modeling and simulation of the physical properties of systems and devices at the nanoscale. The main aim of the software platform is to build a productive environment for a sequential and concurrent multiscaling analysis, connecting the design capabilities of traditional computer aided design software (CAD) at the macroscale and the atomistic representation of matter, as well as provide an intensive use of computational atomistic methods that have been developed by the scientific community to calculate physical properties at the atomic scale. The platform includes a complete atomic editor for molecules, bulk and 0/1/2/3 D materials, that permits the incorporation of almost any type of defects, and it also enables the atomic building and the orientation matching of systems and devices built by CAD or in-platform tools. It also includes a library of materials for a preconfigured analysis, a powerful atomic visualizer for any kind of systems, including atomic representation of real size ensembles, and post-processing tools. Proprietary, third-party and opensource codes from different methodologies and theoretical frameworks are connected through modules that permit the specific generation of input files and an in-platform post-processing. All this features are integrated in a friendly, dynamic, intuitive and innovative graphical user interface that enables an easy use of sophisticated modeling and simulation tools, usually difficult to use, to experts from different worlds. We are open and happy to include and work with new methods that would enrich the n:: CAD platform. References n/a.

Figures

Illustration of scaling

Illustration of defects modeling

Fluorimetric determination of alkaline phosphatase activity in foods using magnetic-gold nanoparticles liposomes hybrids as useful on-flow micro-container devices

Vanessa Román-Pizarro, Juan Manuel Fernández-Romero and Agustina Gómez-Hens Department of Analytical Chemistry. Institute of Fine Chemistry and Nanochemistry (IUQFN UCO) Campus of Rabanales. Marie Curie Building (Annex) University of Córdoba E-14071-Córdoba, Spain. Web site: http://www.uco.es/investiga/grupos/FQM-303 q52ropiv@uco.es Abstract The analytical usefulness of hybrid nanostructures formed by magnetic-gold nanoparticles (Fe2O3-DTAuNPs) into liposomes as on-flow micro-containers for the improvement of the reagent preconcentration and the in-situ development of the analytical reaction/detection is presented. The system supposes the use of an electromagnetic device incorporated into a flow injection system for the development the preconcentration analytical reagents, followed by the liposome release and the “in-situ” development of the analytical reaction/detection. The useful of the system was tested by its application to determination of alkaline phosphatase (ALP) activity in foods. A previous synthesis of the hybrid liposomes containing the magnetic-gold nanoparticles and an appropriate target enzyme substrate was also required.

For the production of the hybrid liposomes a step-by-step synthesis process which including the following stages: (1) Synthesis of Fe2O3-DT-AuNPs, (2) Covering the magnetic nucleus with a gold layer to form magnetic-gold NPs, which were also modified to produce non-polar Fe3O4-AuNPs using 1dodecanethiol. Finally, these Fe2O3-DT-AuNPs were also encapsulated into liposomes with an appropriate surfactant during the liposome formation using the rapid solvent evaporation method. Finally, the hybrid liposomes were slighting resized using mechanical shaking and separated from the un-entrapped NPs using sucrose density gradient centrifugation (SDGC).

A flow injection system equipped with an electromagnetic device was used for develop the automatic preconcentration and enzymatic determination method. The calibration graph of the method was -1 2 defined in a linear range which covered concentration values from 6.4 – 250 mU·L , (r =0.993, n=7, -1 r=3), with a detection limit of 1.1 mU·L . The precision, expressed as relative standard deviation (RSD -1 %) was lower than 2.4 %. The overall method shows a sampling frequency of 10 h . The features of the method was also compared with those features obtained using two more conventional system developed in batch and flow-injection ways. The method was applied to the determination of the enzymatic activity of ALP in milk samples with recovery values ranging between 87.5 and 104.6 %. The method also have been used for the determination of residual ALP activity in milks subjected to temperature treatments with excellent agreement with the conventional method and also provided acceptable recoveries in all instances.

Green way to clay-supported graphenes C. Ruiz-García, M. Darder, P. Aranda and Eduardo Ruiz-Hitzky Instituto de Ciencia de Materiales de Madrid (ICMM), CSIC, c/ Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain cristina.ruizg@icmm.csic.es

Abstract This contribution introduces recent results reporting on the achievement to prepare graphene-like materials from resources as common as carbohydrates (e.g., table sugar) and proteins (e.g., gelatin) supported on diverse porous solids (clays, silica, zeolites,..). These transformations are conducted at relatively moderated temperatures (below 800ºC) in absence of oxygen and, surprisingly, without requiring the presence of reducing agents. Among other porous solids, clay minerals of different topologies, i.e. from layered silicates of the smectite type to fibrous sepiolite, have been used as porous substrates to produce nanostructured carbonaceous materials using diverse molecular and polymeric organic precursors [1-3]. Although the carbon-clay materials may have interest per se, most of the carbon-clay precursors are used as source of nanostructured carbons provided with electronic conductivity useful for diverse applications such as electrode materials for secondary battery electrodes and supercapacitors [4]. Nevertheless, few reports on the use of the carbon-clay intermediates without removal of the porous substrate have been reported, though the presence of the clay substrate may provide additional advantageous features [5,6]. The present contribution will introduce recent results pointing out the possibility to prepare supported graphene-based materials from natural resources, such as sucrose or caramel and two types of clays, i.e. layered clay (montmorillonite) and fibrous clay (sepiolite). Figure 1 shows a schematic representation of the synthetic approaches using sepiolite as porous support. Intermediate clay-caramel nanocomposites can be prepared either by microwave (MW) irradiation of sucrose-clay precursors or by direct silicate impregnation with water-caramel suspensions. The resulting graphene-clay supported materials were obtained by further heating at 700-800 ºC, under nitrogen flow (Fig. 1).

clay support (sepiolite)

sucrose, MW

Δ, ∼800 ºC

(or caramel impregnation)

N2 atmosphere caramel-sepiolite nanocomposite

graphene

graphene-sepiolite nanocomposite

Fig. 1. Schematic representation of the preparation route of supported graphenes on the magnesium silicate sepiolite using sucrose or caramel as precursors. 800

C/SEPIOLITE 600

Intensity (arb. unit.)

The carbon content in the resulting powder samples determined from CHN elemental analyses is around 35% (w/w), which corresponds to graphene-like compounds assembled to the clay support. Deconvoluted C1s peak in the XPS spectrum of thermally treated caramel-clay samples shows that the main contribution corresponds to C=C bonds, which are present as an intense, sharp and very narrow component of graphene-like material. Raman spectrum confirms the graphene formation through the G-band at 1595 cm-1 (sp2 carbon) and the D-band at 1360 cm-1 (disorder in sp2-hybridized carbon) (Fig. 2).

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Fig. 2. Raman spectra of graphene-clay materials showing similar features for the both types of clay substrates, montmorillonite and sepiolite.

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3500

The graphene-clay supported materials show interesting characteristics such as simultaneous conducting behavior, together with chemical reactivity and textural features provided by the silicate backbone, of interest for diverse high-performance applications [7]. In this way the resulting supportedgraphenes based on sepiolite act efficiently as electrodes for lithium-batteries without the usual requirement of conductive additives, and the preliminary results open also the way for applications as components in supercapacitors. However, it is necessary to optimize these systems to improve them in the light of possible real-world applications. The procedure here reported for the synthesis of clay-supported graphenes can be considered as a remarkable eco-friendly approach deserving a relatively low-cost and promising large scale way for graphene-like materials production, especially when comparing with the Hummers’s method and related procedures using graphite as precursor.

Acknowledgements Financial support from CICYT (Spain, MAT2009-09960 and MAT2012-31759) and from the CSICAcademie Hassan II (2010MA0003) is gratefully acknowledged.

References [1] T. Kyotani, N. Sonobe and A. Tomita, Nature 331 (1988) 331. [2] T. Kyotani, H. Yamada, N. Sonobe and A. Tomita, Carbon, 32 (1994) 627. [3] P. Aranda, “Conducting polymer–clay and solid electrolytes”, in Clay-Based Polymer Nanocomposites, eds. K.A. Carrado and F. Bergaya, CMS Workshop Lectures Series Vol. 14, The Clay Minerals Society (Chantilly, 2007) Chap. 6, 173. [4] A. Gomez-Aviles, M. Darder, P. Aranda and E. Ruiz-Hitzky, Angew. Chem. Int. Ed. 46 (2007) 923. [5] R. Fernández-Saavedra, M. Darder, A. Gómez-Avilés, P. Aranda and E. Ruiz-Hitzky, J. Nano-sci. Nanotech. 8 (2008) 1741. [6] E. Ruiz-Hitzky, M. Darder, F. M. Fernandes, E. Zatile, F. J. Palomares and P. Aranda, Adv. Mater. 23 (2011) 5250. [7] C. Ruiz-García, R. Jiménez, J. Pérez-Carvajal, A. Berenguer-Murcia, M. Darder, P. Aranda, D. Cazorla-Amorós and E. Ruiz-Hitzky, Sci. Adv. Mater. (in press).

Simulating the electrostatic interaction of charged thin films by the image charge method and soft computing techniques E. Castellano-Hernรกndez, G. M. Sacha and J. J. Sรกenz Universidad Autรณnoma de Madrid. Campus de Cantoblanco. 28049 Madrid, Spain juanjo.saenz@uam.es Abstract Understanding the electric field effect in nanostructured thin films is a key issue in nanoscience nowadays [1]. Recently, single and Few Layer Graphene (FLG) has attracted much attention because of its atypical response to electrostatic fields, which is in sharp contrast with that expected for conventional conducting or semiconducting films [2]. It has been found that values of the dielectric constant that cannot be found in other materials can be easily distinguishable when the sample structure is a graphene-like thin film [3]. To understand the origin of this effect, we combine numerical methods and soft computing to simulate the electrostatic interaction between an EFM tip and a thin film. Soft computing techniques become very useful in this context when the EFM system is not fully defined and some parameters are free or unknown. Using the electrostatic force as input patterns to the ANN, we establish that the thin film sample and substrate can be replaced by a simple semiinfinite sample characterized by an effective dielectric constant. We show that, for typical EFM setups and thin film thicknesses around 1nm, the electrostatic interaction of thin films with ultrahigh dielectric constants is easily distinguishable. We find that, for these specific thin films, dielectric constants between 500 and 10000 give very different electric responses. To improve the performance of the simulations and the understanding of the electrostatic interaction between thin film layers and metallic EFM tips, we have included a free charge density value to the thin film layer. With this improvement, we are able to study the effects and differences between a dielectric thin film and thin layers with small amounts of charge inside. This effect could be of great interest in the study of thin materials with a high polarizability such as graphene layers since their finite size effects could be understood and characterized by ultrahigh thin film dielectric constants or uniform free charge distributions at the surface.

References [1] [2] [3]

E. M. Vogel. Nat. Nanotechnology. 2, (2007) 25. S. S. Datta, D. R. Strachan, E. J. Mele and A.T. C. Johnson. Nanoletters 9, (2009) 7. E. Castellano-Hernรกndez and G. M. Sacha. Appl. Phys. Lett. 100, (2012) 023101.

Performance of microfluidics in the preparation of O/W nanoemulsions containing green solvents J. Santos; L.A. Trujillo-Cayado; N. Calero; M.C. Alfaro; J. Muñoz Departamento de Ingeniería Química, C/ Profesor García González, 1, Seville, Spain jmunoz@us.es Abstract Emulsions are colloidal thermodynamically unstable dispersions in which a liquid is dispersed in a continuous liquid phase in the form of droplets. Emulsions are used as end or intermediate products in many fields, like cosmetics, food industry, pharmacy, medicine, polymers, catalysts and agrochemistry. The role of solvents in agrochemical industry is becoming increasingly more important. More than 25% of all pesticides contain high concentrations of organic solvents, which represent a fire hazard, may be toxic and contribute to atmospheric volatile compound (VOC) emissions [1]. Thus, many of the classical solvents are being gradually replaced by the so-called ‘green’ solvents, such as fatty acid dymethilamides and D-Limonene. Fatty acid dimethylamides (FAD) are solvents that fulfil the requirements to be considered green solvents and may find application in agrochemicals. D-Limonene, a naturally occurring hydrocarbon, is a cyclic monoterpene, which is commonly found in the rinds of citrus fruits such as grapefruit, lemon, lime, and in particular, oranges. Limonene exhibits good biodegradability, hence it may be proposed as an interesting alternative to organic solvents. α-pinene is also a renewable solvent, which may be obtained from pine resins or distillation. These solvents can meet the ever-increasing safety and environmental demands of the 21st Century. The most common emulsification methods are based on mechanical energy input to the system by an external source. As a rule, emulsions are prepared in two steps; the aim of the first (primary homogenization) is to create droplets of dispersed phase such that a coarse emulsion is formed. The goal of the second step is to reduce the size of preexisting droplets, which usually involves the use of a different homogenizer. Rotor-stator homogenizers, colloid mills, membranes, ultrasonic probes, high pressure- valve homogenizers and microfluidizers are currently used to prepare emulsions [2]. The droplet size distribution (DSD) of the emulsion depends on the emulsification method used. DSD is perhaps the most important factor in determining properties like consistency, rheology or shelf life stability of emulsions. On the whole, emulsions with smaller droplet sizes result in greater physical stability. It is well documented that DSD plays an important role in the retention of volatile and surface oil content of powders during microencapsulation by spray drying [3]. It is interesting to highlight the increasing importance of emulsions with submicron droplet diameter and a narrow DSD in many fields like food, pharmaceutical and cosmetic industries [4]. Typically emulsions with a high percentage of submicron droplets are produced either by using a highpressure valve homogenizer (HPvH) or a Microfluidizer. An HPvH consists of a piston pump and a narrow gap, where a valve reaches an operating pressure of up to 150 MPa. Droplet break-up occurs within the region of the valve gap and in the jet after the gap. A Microfluidizer operates at a similar maximum pressure, generated with a piston pump, and droplet break-up occurs from high turbulence o and shear created by the collision of two impinging jets oriented 180 to each other. Forcing the flow stream by high pressure through microchannels toward an impingement area creates a tremendous shearing action, which can result in exceptionally fine emulsions. Some studies have pointed out that the microfluidization technique is capable to obtain emulsions with lower mean droplet diameters and narrower DSDs than traditional emulsifying devices [5]. The goal of this work was to investigate: a) The influence of emulsification method on the DSD and physical stability of O/W eco-friendly emulsions formulated with a mixture of green solvents (α-pinene and N,N-Dimethyl decan-1-amide (DMA-10)) as oil phase. Four different emulsification methods based on two rotor-stator devices (Ultraturrax T50 and Silverson L5M) and two high-pressure homogenizers (Avestin Emulsiflex C5 and Microfluidizer M110P) have been used. b) The influence of emulsification pressure, from 35 to 172 MPa, on the rheological properties, DSD and physical stability of O/W eco-friendly emulsions containing a mixture of d-limonene and DMA-10 as oil phase.

A glycereth-17 cocoate (Levenol C201 ) has been used as emulsifier. Polyoxyethylene glycerol esters derived from cocoa oil (Levenol) are non-ionic surfactants which fulfil the environmental and toxicological requirements to be used as emulsifiers in order to design eco-friendly products. DSD measurements were perfomed by laser diffraction with a Mastersizer X (Malvern). Multiple light scattering (MLS) scans were carried out with a Turbiscan Lab-expert (Formulaction) for about 75-100 days at 25 ºC, which provided early information on the destabilization kinetics and the main mechanism involved. This technique is able to detect instability problems long before the naked-eye. The rheological measurements were carried out with a CS Haake-MARS rheometer (Thermo), using a sandblasted Z20 coaxial cylinder geometry to avoid slip-effects. Figure 1 illustrates the influence of emulsification method on the values of Sauter mean diameter (d3,2), volumetric mean diameter (d4,3) and span for some representative emulsions processed with four different methods. All methods allowed submicron emulsions to be prepared, but the Microfluidizer M110P and the Avestin EmulsiFlex C5 achieved the lowest Sauter diameters (about 280 nm in both cases). However, the Microfluidizer M110P provided emulsions with lower values of volumetric diameter and span (related to polidispersity) than Avestin Emulsiflex C5. The latter gave rise to an emulsion showing some recoalescence. This phenomenon is currently associated to an excess of mechanical energy input during the emulsification process [4]. In addition, MLS measurements showed that emulsions processed with the Microfluidizer exhibited a higher stability against creaming. This could be ascribed to the lower mean diameters and polidispersity achieved with the Microfluidics. Interestingly, the influence of the homogenization pressure on the DSD in these emulsions was not significant, conversely to rheological properties, which were substantially influenced by the homogenization pressure. All emulsions studied exhibited shear thinning behaviour, which fitted the Cross model. A decrease of emulsification pressure yielded an increase of the zero shear viscosity. This could be related to a flocculation process, which subsequently triggered a coalescence process, as demonstrated by Laser Diffraction. References [1] Höfer, R., Bigorra, J.,Green Chemistry, 9 (2007) 203-212. [2] Urban, K., Wagner, G., Schaffner, D., Röglin, D., Ulrich, J., Chemical Engineering and Technology, 29 (2006) 24-31. [3] Soottitantawat, A., Yoshii, H., Furuta, T., Ohkawara, M., Linko, P., Journal of Food Science, 7 (2003) 2256-2262 [4] Jafari, S.M., Assadpoor, E., He, Y.,Bhandari, B., Food Hydrocolloids, 22 (2008) 1191-1202. [5] Pinnamaneni, S., Das, N.G., Das, S.K., Pharmazie, 58 (2003) 554-558. 750

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Figure 1. Sauter diameter, volumetric diameter and span for emulsions processed with different emulsification methods.

Quantitative study of corrugated graphene by tomography and simulation G. Scavello1, J. Maestre1, J. Pizarro1, S. I. Molina2, P. L. Galindo1 1

Universidad de Cadiz, Departamento de Ingenieria Informatica, Cadiz (Spain) Universidad de Cadiz, Departamento de Ciencia de los Materiales e I. M. y Q. I., Cadiz (Spain)

giovanni.scavello@uca.es Abstract Graphene has been proved to be one of the most versatile materials for nanotechnologies. It is a matter of fact that its properties, such as conductivity or catalytic behaviour, are strongly affected by the lattice configuration of the layer [1]. A non-invasive methodology for the study of the 3D distribution of C atoms in corrugated graphene has been developed and tested on simulated images. The objective is to show how to adapt tomographic techniques to the study of the corrugations in a graphene layer. Electron tomography (ET) is widely used to determine the shape of an object. It deals with the reconstruction of a 3D volume from a set of 2D projections of the object under study. Its application to nanomaterials is relatively recent, because of the limitations of the electron microscopes (resolution, aberration, etc). At atomic scale, classical tomography approaches must be replaced by ad hoc techniques. The 3D information can be obtained by processing the projections and by using geometrical models instead of the classical integral one. In the classical model, the object to be reconstructed is represented by a volume in a 3D space. The 3D p =W ⃗f . reconstruction problem can be afforded by solving a system of linear equations of the type ⃗ To obtain the solution, algebraic reconstruction methods can be used [2]. Usually, in the field of electron tomography, particles are put onto the specimen during the preparation steps such that they are clearly detectable in the series. These particles are used as markers for alignment purposes [3]. Generally, a marker is a part of the specimen that can be easily traced along the whole series. To use a tomographic approach for the quantification of the corrugation, the characteristics of the material can help to develop special-purpose methodologies. For example, a single graphene layer has a simple geometric configuration (honeycomb regular structure) and atomic thickness. Such features can be exploited to simplify the problem and optimize the reconstruction process. In this case, each atom can be considered as a marker. The proposed approach offers many advantages over the classical one • By considering each atom as a marker, it is possible to obtain a direct atomic reconstruction of the structure • By using a small angles range to obtain the images, the obtained series does not suffer from focusing problems (figure 1). • By applying a geometric approach, the reconstruction is faster and the precision is not affected. • By calculating straightforwardly the positions of the atoms in 3D space, the missing wedge problem is greatly alleviated and the effect of the noise reduced (figure 2 a, b). To validate the methodology, a simulated tomography series has been obtained using SICSTEM [4] (figure 1), a parallel software that allows the simulation of high resolution images from large nanostructures. A Nion Ultrastem set up has been used with equally spaced angles from -10° to 10° and a resolution of 100 px/nm. An original approach is proposed for corrugation mapping in graphene monolayers. It is based on tomographic series taken at a very low range angles, locating atoms along the series by exploiting the monolayer feature. It has been proved that this approach minimize the influence of the noise on the reconstructed structure. Moreover, it avoids the drawbacks coming up from the missing wedge and the focusing at high tilt angles. The advantage is a fast but accurate reconstruction and the results are robust with respect to the noise as well as in the use of few projections, especially with low noise levels (figure 3). We consider that the Tomography Through Point approach is useful for the study of the corrugation, and can be considered an effective method in graphene structural analysis [5].

References [1] Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts, R. S. Ruoff, Advanced Materials 22 (2010) p. 3906 [2] F. J. Maestre, G. Scavello, J. Pizarro, P. L. Galindo, IEEE Transaction on image processing 20 (2011) p. 2146 [3] Pawel Penczek, Michael Marko, Karolyn Buttle, Joachim Frank, Ultramicroscopy. 70 (1995) p. 393 [4] J. Pizarro, P. L. Galindo, E. Guerrero, A. YĂĄĂąez, M. P. Guerrero, A. Rosenauer, D. L. Sales, and S. I. Molina, Appl. Phys. Lett. 93 (2008) p. 153107 [5] G. Scavello, J. Pizarro, J. Maestre, S. I. Molina, P. L. Galindo, Appl. Phys. Lett. 101 (2012) p. 213106 Figures

Figure 1: Corrugated graphene monolayer simulated at high tilt angle

a b Figure 2: (a) Atoms' positions of the simulated structure (b) and atoms' positions of the reconstructed structure

Figure 3: Quantification of the error in nm, with respect to the noise standard variation and the number of projections used for the reconstruction of the simulated structures. For more details see [5].

A Facile Approach for Controlled Growth of Metal Oxide Films on Substrates irrespective of Hydrophilic or Hydrophobic Nature 1

Hye Jin Shin , Ha-Jin Lee , and Won San Choi * 1

Abstract The iron oxide (IO) nanoneedle film was prepared from hydrophilic or hydrophobic substrate: needlelike IO nanoparticles (NPs) were grown on the surface of the glass or tetrafluoroethylene (Teflon) substrate by the addition of a mixed aqueous Fe precursor solution to the solution involving substrates and controlled oxidation of the iron precursors under controlled conditions. The surface morphology of the IO film was determined by scanning electron microscopy. As illustrated in the figure, the substrate was uniformly covered with submicrometer-sized needlelike IOs. The length of the IO needles could be controlled by changing the incubation time or cycle of the iron precursor solution. As the reaction time was adjusted from 3 to 12 hours, the average length of the IO needles increased from 300 to 950 nm. Because the iron precursors were supplied to the substrate via surface diffusion in the aqueous [1-3] environment, the shape of the IO needles sharpened as growth proceeded. In the early stage of growth, the IO needles were sparsely distributed and thus laid parallel to the surface of the substrates. By comparison, as the growth proceeded, overcrowding of the IO needles led them to stand up, forming densely packed IO needles with high surface coverage. It is worth noting that the presence of the oxidant helped to activate the surface of substrates regardless of hydrophilic or hydrophobic nature, thus promoting the growth of IO nanoneedles with uniform distribution on any substrates. Even though the glass substrate has many reaction sites, such as negatively charged hydroxyl groups as well as defects, IO nanoneedles were not formed on the substrate in the absence of oxidant. Only in the presence of oxidant, positively charged iron precursors are more favorable for adsorption on the glass or Teflon substrate activated by oxidant. The presence of the IO species on the substrates after synthesis was confirmed by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analyses. The strong diffraction patterns in the XRD data confirmed that the synthesized IO needles were composed of goethite (a-FeOOH) and hematite (a-Fe2O3). After surface modification of IO nanoneedles, Ag NPs were synthesized onto IO nanoneedles. By appropriate treatment, it was possible to transform the Ag NPs into the Ag@AgX NPs on IO nanoneedles (Substrate/IO/Ag@AgCl). We expect that other metal oxide films can also be prepared and the resulting films can be utilized as a versatile film for environmental remediation. Our novel method described here is very useful for coating metal oxides on substrates irrespective of hydrophilic or hydrophobic nature.

References [1] Won San Choi, Hye Young Koo, Jeong-Ho Park, Dong-Yu Kim, J. Am. Chem. Soc. (2005), 127, 16136-16142. [2] Hye Young Koo, Ha-Jin Lee, Hye-Ah Go, Young Boo Lee, Tae Sung Bae, Jun Kyung Kim, Won San Choi, Chem. Eur. J. (2011), 17, 1214-1219. [3] Won San Choi, Hye Young Koo, Dong-Yu Kim, Adv. Mater. (2007), 19, 451-455.

Figures

AgCl

Figure 1. Schematic illustration for synthesis of the IO nanoneedle-like film decorated with Ag@AgCl NPs.

Magnetic films of metal-graphene-polymer nanocomposites 1,2

H. Takacs , B. Viala , C. Gourgon , F. Duclairoir , J.-H. Tortai 1

CEA, LETI, MINATEC Campus, Grenoble, France LTM-CNRS-UJF, CEA, LETI, MINATEC Campus, Grenoble, France 3 CEA, INAC, Grenoble, France 17 rue des Martyrs, 38054 Grenoble cedex 9, France helene.takacs@cea.fr

Abstract Over the years components miniaturization has been a crucial objective in microelectronics resulting in the integration of most of the passive components. To go further, ultra-miniaturization of RF inductors and antennas is yet to be done because it runs up against the paradigm of a highly permeable material with zero macroscopic conductivity. Neither ferrites (too low permeability), nor ferromagnetic alloys (too conductive) meet this requirement. Therefore, a breakthrough is essential regarding the way of developing such material. Here, we are interested in metallic-nanoparticle-loaded polymers with enhanced soft magnetic properties from the bulk. Only metals such as Ni, Co, Fe and alloys (i.e. FeCo) can address high permeability in microwave region due to high natural saturation magnetization (1.6 – 2.2 T). So far mainly ferrites-based nanocomposites (i.e. magnetic oxides) have been elaborated because most of chemistries are highly oxidizing. But magnetic oxides have too low magnetic properties at high frequency, mainly due to the diluted saturation magnetization (0.2 – 0.5 T) [1], [2], [3]. The objective of this work is to synthetize core-shell metallic commercial nanoparticles-based nanocomposites. Original dual core-shell schemes are investigated. First a graphene shell prevents oxidation of the metallic particle core (M/C). Then a (co)polymer (P1) shell insulates the graphenecoated metallic particles (M/C//P1) and controls the inter-particle spacing at a nanometric scale. A second polymer (P2) can be used as an encapsulating matrix of the super beads (i.e. P2 can be P1 as well). Finally films of compacted metal-graphene-polymer (M/C//P1/P2) super particles are deposited on substrates by spin coating. In this work, commercial <30nm> M/C nanoparticles of Co (from Sigma-Aldrich) are used. P1 consists in -1 Pyrene-terminated Polystyrene with three different molecular weights (5.6, 26 and 355kg.mol ), while P2 -1 is pure Polystyrene (molecular weight 35kg.mol ). First ultra-sonication is used to break large aggregates of as-received commercial Co/C nanoparticles into small ones (~100nm). Then P1 is directly grafted on the graphene shell (Co/C//P1). The super particles of Co/C//P1 nanoparticles are further encapsulated with P2 which makes the whole nanocomposite cohesive (Co/C//P1/P2). Finally films of compacted Co/C//P1/P2 material are deposited on silicon substrates by spin coating. The choice of using Pyrene-terminated Polystyrene as P1 is motivated by the presence of four aromatics cycles in Pyrene groups. Delocalized electrons can strongly interact with graphene sheet(s) surrounding NPs through π-π stacking [4]. Pyrene groups are also known to fluoresce and are used as fluorescent labeling agent for biological applications [5]. Here the Pyrene fluorescence peak around 500 nm is used as a marker of grafting onto the NPs. Sedimentation dynamics of the solutions has been studied first. P1-grafting and further addition of P2 stabilize NPs and small aggregates, as can be seen on Figure 1 where relative area of integrated absorbance curves is plotted against sedimentation time, in the case of Co particles. -1

As can be seen on Figure 2, P1-grafting (where Mw(P1)=5.6kg.mol ) can clearly be identified around typical 100 - 200nm aggregates which confirms the strength of π-interactions. Note that observation on single NP is difficult. Figure 3 shows a cross-section of the film of Co/C//P1/P2 nanocomposite. For intermediate thickness (< 1µm), the films consist in a mixture of small aggregates and isolated NPs well dispersed inside the film volume. Such films of Co/C//P1/P2 nanocomposite exhibit a dominant soft ferromagnetic behavior at room temperature as shown on Figure 4 with moderate hysteresis (Hc of 23 Oe). The room temperature saturation magnetization is of 0.35T indicating a volume fraction of Co of about 20% from the bulk. The

relatively high anisotropy (i.e. suitable for high frequency use) may originate in chain-like arrangement of the Co NPs which is under investigation. Finally, when considering thicker film (up to ~ 10µm), soft magnetic properties somehow deteriorate because of the presence of residual large aggregates of big particles (~ 100nm) which remain trapped during spin-coating.

Conclusion Magnetic films of metal-graphene-polymer nanocomposites are synthesized by dispersing Co/C NPs in a PS matrix (P2). The graphene shell is successfully functionalized by grafting Pyrene-terminated PS (P1) via non-covalent interaction (π stacking). These first films of Co/C//P1/P2 consist in a mixture of small aggregates and isolated NPs well dispersed inside the film volume. Soft ferromagnetic-like behavior is observed at room temperature with a saturation magnetization of 0.35T indicating a volume fraction of Co of about 20%. Next steps will consist in increasing this number (~40%) by varying the ratio of Co/C//P1 super particles vs. PS (P2) in the solution. References [1] N. R. Jana, Y. Chen, and X. Peng, Chemistry of Materials, 16 (2004), pp. 3931–3935 [2] Y. Wang, X. Teng, J.-S. Wang, and H. Yang, Nano Letters, 3 (2003), pp. 789–793 [3] B. Frka-Petesic et al., Journal of Magnetism and Magnetic Materials, 321 (2009), pp. 667–670 [4] J. Liu, J. Tang and J. J. Gooding, Journal of Materials Chemistry, 22 (2012), pp. 12435–12452 [5] J. C. Hicks et al., Chemistry of Materials, 18 (2006), pp. 5022–5032

Figures

Fig. 1: Relative area of integrated absorbance curves vs. sedimentation time

Fig. 2: SEM picture of an isolated P1-coated Co/C aggregate

Fig. 3: SEM picture (cross-section) of Co/C//P1/P2 nanocomposite film

Fig. 4: Magnetic response of Co/C//P1/P2 nanocomposite film

Mechanical characterization of nanostructured tungsten films for nuclear applications E. Tejado1, N. Gordillo2,3, M. Panizo-Laiz2 R. Gonzalez-Arrabal2 ,I. FernandezMartinez4,5, J.Y. Pastor1 1

Departamento de Ciencia de Materiales-CISDEM, ETSI de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, Madrid, Spain 2 Instituto de Fusión Nuclear, ETSI de Industriales, Universidad Politécnica de Madrid, Madrid, Spain 3 CEI Campus Moncloa, UCM-UPM 4 Instituto de Energía Solar (IES), Universidad Politécnica de Madrid, Madrid, Spain 5 Instituto de Microelectrónica de Madrid, IMM-CNM-CSIC, Madrid, Spain elena.tejado@mater.upm.es

Due to their use as a shield and structural component plasma facing materials have to fulfil very different requirements: from the stability with respect to high neutron irradiation doses to the ductility within the operation temperature range. Owing to its low sputtering yield and good thermal properties, tungsten seems a promising candidate material for plasma-facing components in next nuclear fusion devices. For practical applications, tungsten coatings are being assessed for use instead of bulk tungsten components solving the problem of heavy weight of W. In order to investigate the technological feasibility of a W coating on a ﬁrst wall structure, nanostructured tungsten thin films were deposited onto stainless steel, molybdenum and silicon substrates by DC magnetron sputtering. The characteristics of the film properties such as adhesion, grain size and morphology have been investigated by Scanning Electron Microscopy (SEM), while the mechanical response of the different coating-substrate systems was characterized using the nanoindentation and nanoscratch techniques. The cross-sectional SEM images revealed that the films morphology is formed by columnar grains with and average grain size of 100 nm. Hardness values deduced from nanoindentation curves by statistical average on each sample is 14 GPa for all the films deposited, three times larger than the one reported for coarse-grain W.

Impact of excitonic-vibrational coupling in a single colloidal quantum dot emission spectrum1 Andre Neumann, Jesicca Lindlau, Alexander Högele Ludwig – Maximilians University, Munich, Germany Jenya Tilchin, Georgy I. Maikov, Maya Isarov, Efrat Lifshitz Israel Institute of Technology – Technion, Haifa, Israel

Colloidal quantum dots (CQDs) implementation in optoelectronics is limited by internal material imperfections such as a fluorescence intermittencies (blinking) and its spectral stability (spectral diffusion). Both the effects originate in the material ability of extra energy exclusion from the system and closely packed charges. A turning point occurred when a few distinctive systems with blinking free behavior were reported in CQDs with either type – I, type – II or quasi – type – II core/shell configurations. The particular interest gains the material with quasi – type – II configuration and a graded interface 2 composition such as CdTe/CdTexSe1-x . This graded composition gives rise to the smooth quantum confined boundaries resulting in the reduction of the non – radiative Auger process and paving the way for non – blinking material and permitting the carrier to interact with a particle surrounding. Since, the CQDs prepared in the wet chemical method, they passivated with organic ligands protecting shell. The ligands shell plays an important role for hot carriers cooling preventing phonon bottle neck in the inter band relaxation processes3. This occurs due to sufficient energy losses of the hot carriers to the ligands vibrational modes. In this work we explore the role of the ligands vibrational degrees of freedom on band edge exciton recombination and the blinking effect/ spectral stability in single (A) CdTe/CdTexSe1-x and (B) CdSe/CdSexS1-x CQD capped with oleic acid (OA). Along this we present an ability of simultaneous detection of both infrared - and Raman active modes using CQDs spectroscopy. The major difference between the materials lies in their ability for electron delocalization over the entire core/shell structure. CdTe/CdTexSe1-x builds pronounced type – II structure while in CdSe/CdSexS1x an uncertainty in the conduction band alignment between CdSe and CdS enables carrier delocalization depending on the shell thickness and composition. Electron wave function penetration to the particle surface enhances the exciton coupling to the ligands vibrations opening the alternative channel for the relaxation. Control experiments with ligand exchange to hexadecylamine (HDA) and performing ZnS buffer shell were done. In the first, we observed a change in vibrational modified emission lines. While in the last, no exciton – ligand vibrational modes coupling was observed. A representative spectra of CdTe/CdTexSe1-x - OA (green), CdTe/CdTexSe1-x - HDA (black) CdSe/CdSexS1-x/ZnS - OA (red) and FTIR of free OA (blue) are shown in figure (left panel). The CdTe/CdTexSe1-x - OA shows similar emission lines detuned from the exciton transition, while CdTe/CdTexSe1-x – HDA possesses a different emission lines. This occurs due to the exciton coupling to the different vibrational modes of the surface capping ligands. At the same time ZnS passivated particle does not exhibit any vibration induced structure due to the spatial separation of the exciton wave function from the particle surface. The left panel of the figure shows a representative plots of PL spectra recorded over time span with acquisition time 1 sec of CdTe/CdTexSe1-x – OA (upper) and CdSe/CdSexS1-x/ZnS OA (bottom). The insets show the TEM image of the measured material. One can see that the exciton coupling to the ligand vibration stabilize the material emission, i.e. the material has a non-blinking behavior and has less pronounced spectral diffusion.

References: 1 2 3

in preparation Osovsky et al., Phys. Rev. Lett. 102, 197401 (2009) Guyot-Sionnest et al., Journal of Chemical Physics 123, 074709 (2005)

Figure: Left panel: FTIR spectrum of free OA (blue), PL spectra of CdTe/CdTexSe1-x – OA (green), CdTe/CdTexSe1-x – HDA (black) and CdSe/CdSexS1-x/ZnS - OA (red). Right panel: PL spectra recorded over time span with acquisition time 1 sec of CdTe/CdTexSe1-x – OA (upper) and CdSe/CdSexS1-x/ZnS - OA (bottom). Insets: TEM images of the measured materials.

Multisource Nanoenergy Harvesting and Storage in the Mechanical Domain F. Torres, O. Súchil, P. Bramon, M. López, J. Agustí and G. Abadal Departament Enginyeria Electrònica, Universitat Autònoma de Barcelona, Edifici Q, Campus Bellaterra, 08193 Bellaterra, Spain Francesc.Torres@uab.cat Abstract Introduction The research regarding green and sustainable micro and nanosystems has experimented an important increase from few years ago until now. Our work is directly related with this kind of research, specifically with two important parts of it, the generation of the energy to feed the micro/nanoelectronic systems and its storage. The main motivation is the study of new challenges in the energy harvesting research: the needs for new sources, mechanisms and technologies at the nanoscale. For the energy generation, our research follows two energy harvesting strategies based on nonlinear bistable approach and on MEMSTENNA concept. Both strategies could be merged onto one system only, as it is shown below. For the energy storage, our work is based on a non-classical way, different from which is used by standard batteries which consists on the mechanical energy storage, and follows different ways, but the main one is based in pressing/bending an array of fine wires system [1]. The common denominator of our mechanical storage approach is to load some kind of spring and maintaining this load with a ratchet potential. This approach could maintain the storage energy unlike the batteries based on charge stored, which suffer a certain discharge during time. Energy Harvesting: Bistable Approach Based on the research done by the group of professor Gammaitoni [2] our work uses a cantilevers system subjected to a bistable potential which, using ambient vibrations as noise, the cantilevers could jump from one of the potential minimum to the another one and due to this generates energy useful for the system to be powered. This bistable approach has the important advantage that does not need to be designed specifically for one ambient vibration frequency due to the fact that movement of the cantilever does not depends on an excitation at its natural frequency but only on the “noise” of the ambient vibrations. We have used a commercial AFM cantilever near to a fixed tip at a certain distance [3]. The bistable potential is got putting an electrical charge of the same sign just in the tip of both the AFM cantilever and the fixed part (see figure 1.A). Using an optical measurement system and changing the distance between the tips, we can measure the jumps between potential minima as is showed in figure 1.B for three different distances. The shorter distance maintains the tip on one of the two minimums of the potential and the longest one has not two minimums of the potential. MEMSTENNA MEMSTENNA is a MEMS based rectenna energy harvester that converts a RF signal into direct current electricity. We have used the same AFM tip presented in the previous section as a MEMSTENNA and a dipole antenna to excite it. We have worked in near field conditions, placing the MEMSTENNA near to dipole antenna. Using an optical detection system (the same system used in previous section), we have measured the vibration of the MEMSTENNA and also we have used a piezoelectric vibrometer to excite it in order to compare both excitations. As we can see in figure 2.A and 2.B the response of the MEMSTENNA follows perfectly the mechanical excitation if the frequency of the dipole antenna is matched with the natural frequency of the AFM tip, but the response of the MEMSTENNA is a convolution between mechanical and RF excitations if the frequency of the emitter dipole antenna is a little bit different than the natural frequency. It is important to point out that our approach for bistable potential and MEMSTENNA uses the same system and thus, we can use both energy harvesting approximations at the same time. Mechanical Battery Related with energy harvesting, the researchers look for energy storage systems compatible with the small dimensions. Our purpose is a battery based on mechanical storage rather than electrical storage with the advantage of durability of the energy stored (ideally the battery do not suffer any discharge process) and, depending on the material, it can store a great amount of energy per unit volume or mass

[4]. We are working on two ways: batteries based on mechanical press or bend of a system of fine wires and the other one we are working on the charging process using thermoactuated or photoactuated materials, which change their dimensions through applying thermal energy or light. For the fine wire based battery, we have chosen ZnO fine wires due to the fact that they could be grown using a simple and cheap process, so called hydrothermal process [1]. We have done a lot of experiments changing the variables of the growth in order to achieve the best way to produce the best fine wires for our purposes (high density, good adhesion to the base of the battery, width and length) [5]. We have worked on changing the temperature, solvent concentrations and initial pH of the solution. We have calculated the maximum stored energy and we have fixed as the maximum value for the load we can apply to the system the one that produces the linear buckling and also using a young modulus of 16.2 GPa taken from the literature [6]. We obtain values from the low capability of energy 3 storage limit: a critical strain of εc = 0.0034 and energy per unit volume U = 95 kJ/m ; to the high 3 capability of energy storage limit: εc = 0.09 and U = 91 MJ/m . In order to calculate critical strain and maximum storage energy, we have taken statistical values of length and width from each experiment and we have applied linear elastic theory and also we have compared our calculations with the results using Finite Elements Methods commercial software (Comsol Multiphysics [7]). This work was financed by ZEROPOWER project FP7-ICT-2009-6, EXPLORA project TEC2010-10459-E and with a collaboration of CONACYT coordinated by the Mexican government. References [1] Z. L. Wang, Materials Science and Engineering R, 64 (2009) 33. [2] F. Cottone et al., Physical Review Letters, 102 (2009) 080601. [3] M. López-Suárez et al., Applied Physics Letters, 102 (2013) 153901. [4] F.A. Hill et al., Nanotechnology, 20 (2009) 255704. [5] O. Súchil et al., Nanoenergy Letters, February 2013. [6] M. Riaz et al., Journal of Applied Physics, 104 (2008) 104306. [7] www.comsol.com Figures

B 6

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Figure 1. A) Sketch of the system used (the left image) and calculation of the bistable potential at different distances between both tips. B) Measurement of tip jumps. A

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Figure 2: A) Comparison between piezo excitation and antenna excitation tuned at the same frequency. B) Example of detuning between antenna frequency and cantilever natural frequency. C) SEM image of a detail of the forest of ZnO fine wires.

B 6

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Figure 1. A) Sketch of the system used (the left image) and calculation of the bistable potential at different distances between both tips. B) Measurement of tip jumps. A

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Charge Transfer in Carbon Nanotubes-Supported Nanoparticles Béatrice Vanhorenbeke

1,2†

2‡

2†,3

, Delphine Bouilly , Richard Martel

, Sophie Hermans

Institute of Condensed Matter and Nanosciences (IMCN), Université catholique de Louvain, Place Louis Pasteur 1, 1348 Louvain-la-Neuve (Belgium) 2† ‡ Département de Chimie and Département de Physique, Université de Montréal, C.P. 6128 Succursale Centre-Ville, Montréal QC H3C 3J7 (Canada) 3 Regroupement Québécois sur les Matériaux de Pointe (RQMP) beatrice.vanhorenbeke@uclouvain.be

Abstract Due to their outstanding mechanical and electrical properties, carbon nanotubes (CNTs) are being considered as promising materials in various fields such as electronic, materials engineering, sensor design and catalysis. A potential application of this carbon allotrope consists of using it as support of nanoparticles for heterogeneous catalysis. Aiming this, we chose bimetallic clusters as precursors of metallic catalysts nanoparticles from which a synergic effect between both constituting metals is expected. Moreover, the size and composition of the activated metallic nanoparticles can be easily controlled by selecting the appropriate starting cluster. More specifically, we synthesized a Ru5Pt cluster [1] compound. In order to coordinate this cluster on the surface of CNTs, we developed a four-steps functionalization pathway: (i) covalent functionalization of carbon nanotubes by diazonium salt; (ii) derivatization of the functionalized nanotubes in order to anchor a ligand for cluster coordination; (iii) cluster coordination; and eventually (iv) thermal activation (Figure 1). At the end of this process, we obtained ‘naked’ Ru-Pt nanoparticles supported on carbon nanotubes, which are expected to exhibit [2] catalytic activity. Using individual single-walled carbon nanotubes field-effect transistors (SWNT-FETs, Figure 2a), we measured the electrical response of those carbon nanotubes-supported bimetallic nanoparticles. Measurement of functionalized-carbon nanotubes revealed a high loss of conductance (70 to 80 %) compared with pristine-CNTs. This result is due to the covalent nature of the functionalization step, [3] which alters the aromaticity of the nanotube. Modification of the grafted moieties does not change the electrical characteristics, since the tube is not further altered by these steps. During thermal annealing, activated nanoparticles are deposited on the carbon nanotube surface. After this activation step, carbon nanotubes recover about 60 % of their initial conductance. Moreover, these measurements show evidence of a charge transfer from the nanotube to the nanoparticle, as revealed by the p-doping of the carbon nanotubes (Figure 2b). This charge transfer is of significant relevance for catalytic applications, since the nanoparticle can be viewed as an electron sink. In summary, we have covalently grafted Ru5Pt clusters on single-walled carbon nanotubes. After thermal activation, we obtained bimetallic nanoparticles-decorated carbon nanotubes. Electrical characterization of those nanohybrids revealed a charge transfer between nanoparticles and carbon nanotubes as evidenced by p-doping of CNTs. Those materials are expected to exhibited catalytic activity.

References [1] S. Hermans, T. Khimyak, B. F. G. Johnson, J. Chem. Soc. Dalton Trans., (2001) 3295. [2] a) R. Raja, T. Khimyak, J. M. Thomas, S. Hermans, B. F. G. Johnson, Angew. Chem. Int. Ed., 40 (2001) 4638; b) Y.-L. Yao, Y. Ding, L.-S. Ye, X.-H. Xia, Carbon, 44 (2006) 61; c) J. Li, Y. Liang, Q. Liao, X. Zhu, X. Tian, Electrochim. Acta, 54 (2009) 1277. [3] J. Cabana, R. Martel, J. Am. Chem. Soc., (2007) 2244.

Figures

Figure 1. Reaction scheme of the functionalization pathway developed for the formation of [Ru5Pt] nanoparticles on carbon nanotubes.

(a)

(b)

This work by James Hedberg is licensed under a Creative Commons AttributionNonCommercial-ShareAlike 3.0 Unported License. .

Figure 2. (a) Schematic representation of a CNT-FET; (b) Charge transfer in carbon nanotubes supported nanoparticles.

Improving the Electrochemical Performance of Graphene Nanosheets as Anode in Half and Full Lithium-Ion Cells Oscar A. Vargas C., Álvaro Caballero, Julián Morales Instituto Universitario de Investigación en Química Fina y Nanoquímica. Departamento de Química Inorgánica e Ingeniería Química. Campus de Rabanales. Universidad de Córdoba, 14071, Córdoba, Spain z82vaceo@uco.es

Abstract Graphene based materials have raised increasing interest for their outstanding properties and numerous applications [1]. Research in Li-ion batteries is not an exception, in particular regarding to anode materials with higher performances in replacement of the commercial graphite. Graphene nanosheets (GNS) as electrode for lithium batteries are produced by several methods, being the reduction of graphitic oxide with hydrazine one of the most studied [2]. Graphene nanosheets (GNS) were prepared from graphitic oxide in aqueous solution with N 2H4 (1 M) as reducing agent, at 100 ºC during 6 h reflux. Figure 1 shows X-ray and transmission microscopy analysis, these reveal an o

amorphous carbon structure with characteristic signatures at 2θ values of about 25 and 42 , and the typical, thin graphene layers with micrometric growth in two dimensions.

Figure 1. X Ray diffractogram and Transmission Electron Microscopy image of GNS

Figure 2 shows the electrochemical properties of GNS in half cells (vs. Li metal electrode) and full cells (vs. LiFePO4 as cathode). In half cells the material (black line) can deliver a reversible capacity of ca. -1

600 mAh g at the end of 30 cycle. However, drawbacks such as the high irreversible capacity during the first cycles (marked with a black ellipse) are still limiting the applicability of the graphene-based materials in full lithium-ion cells. There are some strategies to overcome these drawbacks. [3, 4, 5] The strategy used here consists of a pre-lithiation of the anode through a contact treatment; the anode was placed in contact under pressure with Li foil soaked in LiPF6 based electrolyte for 5 min. As a result of this treatment the electrolyte is partially decomposed over the surface of graphene, forming the so +

called Solid Electrolyte Interface (SEI); such SEI formation has consumed enough Li as to reduce the

irreversible capacity in the first cycles, as it is evident from the pre-lithiated curve (red line) in the half cells of Fig. 2.

Figure 2. Half cells with and without treatment. Full cells, comparison between Graphite and GNS

Finally, with the pre-lithiated anode a full Li-ion cell has been assembled with LiFePO4 as cathode. The -1

so formed cell exhibits an average capacity of ca. 120 mAh g over 30 cycles (red line in the full cells of Fig. 2), a higher capacity than that of a similar full cell made with commercial graphite as anode. In spite of the excellent initial performance, the maintenance of capacity is still an aspect to be optimized.

References [1] [2] [3] [4] [5]

D. A. C. Brownson, C. E. Banks, Analyst 135 (2010) 2768 O. A. Vargas C., A. Caballero, J. Morales, Nanoscale 4 (2012) 2083 F. Bonino, S. Brutti, P. Reale, B. Scrosati, L. Gherghel, J. Wu, K. MĂźllen, Adv. Mater. 17 (2005) 743 A. Caballero, L. HernĂĄn, J. Morales, ChemSusChem 4 (2011) 658 J. Hassoun, K. S. Lee, Y. K. Sun, B. Scrosati, J. Am. Chem. Soc. 133 (2011) 3139

Paclitaxel encapsulated magnetoliposomes as drug carrier and magnetic hyperthermia device Roberta Viana Ferreira and Rosana Zacarias Domingues Departamento de QuĂmica, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil robertavia@gmail.com Abstract In this work, we prepared magnetoliposomes with different concentrations of magnetic nanoparticles and investigated the possibility of using the corresponding formulation for cancer treatment. Then we choose the best formulation based on magnetoliposome and used to prepare paclitaxel encapsulated magnetoliposomes. The possibility of using the corresponding formulation for controlled drug release and cancer treatment by taking advantage of its hyperthermic behavior was investigated. Magnetic nanoparticle was synthesized by co-precipitation of ferrous and ferric salts in alkali medium of ammonium hydroxide and functionalized with citric acid to obtain a ferrofluid. The ferrofluid was used to prepare a series of magnetoliposomes containing different concentrations of magnetic nanoparticle. The amount of encapsulated magnetic nanoparticles was determined based on ferrous ion by using ophenanthroline and phospholipid concentration of samples was determined following the method colorimetric assay. Magnetic nanoparticle encapsulation efficiency was dependent on the initial amount of ferrofluid present at the encapsulation stage and to the best formulation we found 66%. We choose this formulation to study physical-chemical properties and to encapsulate paclitaxe. Encapsulation efficiency of the drug was also evaluated in presence of different magnetic nanoparticle concentration. At very high concentrations there is a reduction in the amount of encapsulated drug, but this reduction is not significant. The mean size and distribution of the particle size were determined by dynamic light scattering and Zeta Potential was measured. All magneliposomes formulations, presented mean size values of about 150 nm and a polydispersivity index of > 0.2, thus having acceptable characteristics for systemic administration. The magnetoliposome showed stability in water for was at least one weak that was examined using UV-vis spectrophotometer and dynamic light scattering (DLS). Magnetic heating under an applied magnetic field was investigated for different magnetic field intensity and the magnetolipossome investigated showed temperature variation appropriate to cancer treatments. References [1] Ferreira, R.V., Pereira, I.L.S., Cavalcante, L.C.D., Gamarra, L.F., Carneiro, S.M, Amaro, Jr E., . Fabris, J.D, Domingues, R.Z. Synthesis And Characterization Of Silica-Coated Nanoparticles Of Magnetite. Hyperfine Interactions. [2] Gonzales, M., Krishnan, K. M. Synthesis Of Magnetoliposomes With Monodisperse Iron Oxide Nanocrystal Cores For Hyperthermia. Journal Of Magnetism And Magnetic Materials, V.293, 265270, 2005. [3] Cosco D., Paolino D., Cilurzo F., Casale F., Fresta M. Gemcitabine And Tamoxifen-Loaded Liposomes As Multidrug Carriers For The Treatment Of Breast Cancer Diseases. International Journal Of Pharmaceutics, 422 (2012) 229â&#x20AC;&#x201C; 237. [4] Paola Crosasso, Maurizio Ceruti, Paola Brusa, Silvia Arpicco, Franco Dosio, Luigi Cattel. Preparation, Characterization And Properties Of Sterically Stabilized Paclitaxel-Containing Liposomes. Journal Of Controlled Release, 63 (2000) 19â&#x20AC;&#x201C;30. [5] Raimon SabatĂŠ, Ramon Barnadas-5RGUĂ&#x2022;JXH] -RVp &DOlejas-FernĂĄndez, Roque Hidalgo-Alvarez, Joan Estelrich. Preparation And Characterization Of Extruded Magnetoliposomes. International Journal Of Pharmaceutics, 347 (2008) 156â&#x20AC;&#x201C;162.

Figures

Figure 1: (a) Representation of paclitaxel loaded magnetoliposome; (b) Transmission electron microscopic (TEM) picture of magnetic nanoparticles.

64 62 60

MagL

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Figure 2: Magnetic hyperthermia studies for magnetoliposomes (MagL) and paclitaxel encapsulated magnetoliposomes (MagLPX).

Redox-Responsive Controlled Gene Transfection Based on Polymer-Conjugated Magnetic Nanoparticles Zhang Lei, Jimmy C. Yu Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China jimyu@cuhk.edu.hk Abstract Gene transfection is a non-viral therapy on gene-based diseases by delivering nucleic acids into the nucleus of target cells1. The efficiency of gene transfection may be enhanced by magnetofection which involves magnetic nanomaterials (MNPs) under a magnetic field2. To combine nucleic acids with nanoparticles as well as protect them from degradation after endocytosis, MNPs are usually modified with cationic compounds, such as 25 kDa branched polyethylenimine (PEI) 3,4. After cationic adsorption of plasmid DNAs on the surface of negative charged MNPs, addition of extra free PEI is often required to form a ternary complex for magnetofection5. It is because only the cationic compounds could transfer the nucleic acids into the cell nucleus, while the MNPs stay only in the perinuclear region. In this work, a redox-responsive disulfide bond is used to link 25 kDa PEI to MNPs, generating detachable PEIs for both DNA protection and nuclear entry. The as-synthesized MNPs were first wrapped in silica with thiol groups on the surface. After thiolexchanging with 2-carboxyethyl-2-pyridyl disulfide, PEI was linked to the carboxyl groups with EDC/NHS. The results of agarose gel electrophoresis indicated that 10 g Fe3O4 nanoparticles could condense 250 ng pRL-CMV, i.e., renilla luciferase control reporter vectors (Fig. 1). Repeated experiments indicated that the condensing nanoparticles were stable for at least one month. The magnetic gene carrier exhibited efficient gene transfection in both Hela and HepG2 cells lines (Fig. 2). After addition of 10 mM glutathione (GSH) in phosphate buffer solution (pH=7.4), plasmid DNA was released from the nanoparticles, confirming the redox-responsive property of the modified magnetic nanoparticles (Fig. 3). The confocal microscopy images showed the labeled plasmid DNA located in the nucleus 3h posttransfection, which was more obvious 24 h after transfection (Fig. 4). In addition, the yellow colored area indicated a significant portion of PEI co-localized with the red florescent lysotracker, suggesting that the magnetic nanoparticles were taken into the cells via the endocytosis pathway. The colocalization of PEI and plasmid DNA in the nucleus confirmed the nucleic acids were taken in with the help of PEI, while nanoparticles were still in the perinuclear region. References [1] Feldman, A. L.; Libutti, S. K. Cancer (2000), 89, 1181. [2] Plank, C.; Schillinger, U.; Scherer, F.; Bergemann, C.; Rémy, J. S.; Krötz, F.; Anton, M.; Lausier, J.; Rosenecker, J. Biological Chemistry (2003), 384, 737. [3] Wang, X.; Zhou, L.; Ma, Y.; Li, X.; Gu, H. Nano Research (2009), 2, 365. [4] McBain, S. C.; Yiu, H. H. P.; El Haj, A.; Dobson, J. Journal of Materials Chemistry (2007), 17, 2561. [5] Ma, Y.; Zhang, Z.; Wang, X.; Xia, W.; Gu, H.; International Journal of Pharmaceutics (2011), 419, 247.

Fig1. Evaluation of the DNA condensing ability of sFe3O4@SiO2-SS-PEI with agarose gel electrophoresis gel assay. Different weight of nanoparticles was incubated with 250 ng pRL-CMV for 20 min at room temperature.

Fig 2. pRL-CMV released at different endpoints after addition of 10mM GSH. Plasmid DNA was mixed with different amount of sFe3O4@SiO2-SS-PEI, and magnet was used to separate the condensed DNA on nanoparticles with the DNA in the supernatant.

Fig 3. Evaluation of the transfection efficiency using luciferase assay: (a) in Hela cell line; (b) in HepG2 cell line. The activity was measured at 48h post-transfection.

Fig 4. Tracking of different components in Hela cells 1 h (a), 3 h (b) and 24 h (c) post-magnetofection. Nucleus was labeled by Hochest 33342, lysosome with LysoTracker速 Red DND-99, PEI with FITC, and plasmid DNA with Cy5.Merged images with bright field were also shown in the right coloumn.