NANOPOSTER 2016
Synthesis of Nanomagnetic Fluids and Their UV Spectrophotometric Response With st Aliphatic Organic Acids and 1 Tier Dendrimers a Pandya ,
Shivani R Man Singh* Centre for Nanoscience, Central University of Gujarat, Gandhinagar-382030 Email: shivpan02@gmail.com, *mansingh50@hotmail.com
Abstract: Synthesis of Magnetic nanoparticles were made using coprecipitation method on mixing Fe+3 and Fe+2 in 2:1 ratio with aqueous 8M NaOH which on heating at 90°C for 2 h has yielded 85% magnetic (Fe3O4) nanoparticles (MNPs), characterized by XRD, VSM, SEM, and HR-TEM . The formic acid (FA), oxalic acid (OA) and citric acid (CA), the series of aliphatic organic acids along with Trimesoyl 1, 3, 5 tridimethyl malonate (TTDMM), trimesoyl 1, 3, 5 tridiethyl malonate (TTDEM), trimesoyl 1, 3, 5 tridipropyl malonate (TTDPM), trimesoyl 1, 3, 5 tridibutyl malonate (TTDBM) and trimesoyl 1, 3, 5 tridihexyl malonate (TTDHM) 1st tier dendrimers were used separately for preparing nanomagnetic fluid. From 25 to 150 μM MNPs at an interval of 25 μM were dispersed in 150 μM acids and dendrimers separately with DMSO. UV-VIS spectrophotometry showed maximum MNPs dispersion with TTDMM against others and found to be most stable nanomagnetic fluid on account of capping type mechanism of acids.
INTRODUCTION
XRD AND HR-TEM
Preparation of stable magnetic fluid (MF) is important to make it applicable in various fields like cells separation, MRI contrast agents, magnetic drug targeting and delivery, memory storage dives and many more. In this work we have developed stable MF using series aliphatic organic acids and dialkyl malonate ester terminated 1st tier dendrimers. Synthesized MNPs were characterized for their physiological, morphological and geometrical properties and MF have been monitored through UV-Vis spectrophotometry. On the bases of our results found from experiment TTDMM-MNPs shows higher stability than other capping agents in DMSO. This study may open a new window of metallodendrimer based MF for emerging wide range of applications.
(a)
(b)
(c)
Figure. 1. (a) XRD spectra of synthesized MNPs, (b) HR-TEM, and (c) SAED pattern of MNPs
OBJECTIVES Synthesis of Fe3O4 nanoparticles and their characterization for confirmation Preparation of MF using aliphatic organic acids and 1st tier dendrimers in aprotic polar solvent
SYNTHESIS OF MNPs 0.2 M FeCl3
To confirm the crystalline structure of Fe3O4, an XRD spectrum was assessed. The diffraction peaks found with the reference of pattern correspond to relative intensity indexed of the Fe3O4 with cubic spinel structure. The HR-TEM of MNPs shows condense, close to the spherical shaped nanoparticles with 17 nm size. The selective area electron diffraction (SAED) reveals the high crystalline nature by showing dot pattern ring.
VSM AND SEM The magnetization saturation (Ms) of MNPs was determined using VSM at 300K with applied magnetic field of 4T and was found as 64 emu/gm. The SEM micrograph shows crystalline structure of molecular geometries distributed in variable sizes. The micrograph also specifies their self-aggregation which seems to produce spherical clusters with very narrow size distribution.
Figure. 3. Optical activities of MNPs with (a) Organic acids, (b) 1st tier dendrimers, and (c) RI of MNPs with Organic acids and dednrimers in DMSO
However, increase in alkyl chain of dendrimers results in decrease in stability of the fluid due to effect of London Dispersion forces which occurred due to steric hindrances formed in alkyl chains.
0.1M FeSO4.7H2O
2h
2FeCl 3( aq) FeSO 4( aq ) 8 NaOH ( aq) Fe3O4 ( S ) 6 NaCl ( aq) Na 2 SO4 ( aq ) 4H 2O 90
CONCLUSION 8M NaOH
Figure. 2. (a) Magnetization saturation graph at 300K, and (b) SEM micrograph of MNPs
RESULTS AND DISCUSSION 1000 rpm,
MNPs
90°C 2h.
washing
Magnetic decantation
2-3 times
Schematic representation: Synthesis of MNPs by Coprecipitation method
Optical activities of nanomagnetic fluids with UV-Vis spectrophotometry and Refractometry Optical activity of nanomagnetic fluid is found higher with citric acid of aliphatic organic acid due to hydrophic-hydrophilic attraction between DMSO and citric acid which partially interact with MNPs and make whole fluidic system stable as compared to other organic acids by decreasing overall attraction between molecules.
These studies conclude that the steric effect of citric acid on stabilization of MF as compared to FA and OA aliphatic organic acid with lower stability. However, increase in dialkyl chain of dendrimers decreases the stability of MF due to Induction effect which caused by dialkyl chain and London dispersion forces developed between solvent and solute. And hence, TTDMM without dialkyl chain in their structure shows maximum stability of MF in DMSO which could be used for potential applications. Acknowledgments Authors are thankful to Central University of Gujarat, Gandhinagar, for infrastructural support. Also thankful to Department of Forensic Science, Gandhinagar, Gujarat for SEM-EDX analysis and magnetization lab, UGC-DAE Consortium for Scientific Research, Indore center for VSM measurements. Reference: (1) Pandya, S. R., Singh, M., Dispersion and optical activities of newly synthesized magnetic nanoparticles with organic acids and dendrimers in DMSO studied with Uv/vis spectrophotometry. J. Mol. Liq. 2015, 211, 146-156.