Bo Song, Huajun Yuan, Cynthia Jameson, Sohail Murad, Chemical Engineering Department Primary Grant Support: US Department of Energy
Problem Statement and Motivation •
Understanding the interaction between nanoparticles and biological membrane is of significant importance in applications in cell imaging, biodiagnostics and drug delivery systems.
•
Some basic questions explored: • How do nanoparticles transport? • What structural changes occur? • Can a lipid membrane heal?
•
Use molecular dynamics simulations to develop better understanding of the transport process and characterization of nanoparticles.
•
Investigate the elastic and dynamic properties of lipid membrane, during the permeation of the nanoparticles.
Key Achievements and Future Goals
Technical Approach • • • •
Used various sizes of nanocrystals as probes. Used coarse-grained dipalmitoylphosphatidy-lcholine (DPPC) lipid bilayers as a simple model membrane. Explored the transport of nanocrystal across DPPC lipid bilayers Investigated the changes in the structural and mechanical properties of DPPC bilayers during permeation.
• • •
Used coarse-grained models to simulate nanoparticles and biomembrane systems successfully. Examined the permeation process of nanoparticles through lipid membranes and the response of lipid membrane at the fundamental molecular level. Explored the effect on transport across a lipid membrane arising from surface coatings on the nanoparticles.
Bo Song, Huajun Yuan, Cynthia Jameson, Sohail Murad, Chemical Engineering Department Primary Grant Support: US Department of Energy
Problem Statement and Motivation •
Understanding the nanoparticle permeation mediated water/ion penetration and lipid molecule flip-flops is of significant importance in drug delivery systems and cytoxicity.
•
Some basic questions explored: • How many water molecules and ions may leak during nanoparticle permeation? • How do water and ion leakages depend on the physical properties of the nanoparticle and the surrounding environment? • How do individual lipid molecules respond when nanoparticle, water and ions permeate simultaneously?
•
Use coarse-grained molecular dynamics simulations technology.
Key Achievements and Future Goals
Technical Approach • • •
Used bare gold nanoparticles as model nanoparticles. Coarse-grained dipalmitoylphosphatidy-lcholine (DPPC) lipid bilayers were used as a simple model membrane. Investigated the effect of NP size, permeation velocity, pressure and ion concentration gradient effects.
•
Used coarse-grained models to simulate nanoparticles and biological membrane systems successfully.
•
Examined the permeation process of nanoparticles through lipid membranes at the fundamental molecular level.
•
Examined the water/ion penetration and lipid molecule flip-flop during the nanoparticle permeation.
Randall J. Meyer, Department of Chemical Engineering, University of Illinois at Chicago in collaboration with Dr. Jeffrey Miller, Chemical Sciences and Engineering Division, Argonne National Lab Supported by NSF grants CBET 0747646 and CBET 1067020
Problem Statement and Motivation
Industrial catalyst
•
Finite fossil fuel reserves dictate that new solutions must be found to reduce energy consumption and decrease carbon use
•
Current design of catalysts is often done through trial and error or through combinatorial methods without deep fundamental understanding
•
Our group seeks to combine experimental and theoretical methods to provide rational catalyst design
100 x 100 nm Model Catalyst
Computational model
Key Achievements and Future Goals
Technical Approach •
•
A combination of experimental methods is employed to characterize catalysts: • X-ray Absorption Spectroscopy (XAS) is used to identify local structures and to determine electronic structure changes in alloys • Scanning Transmission Electron Microscopy is used to provide structural models for catalytic active sites with atomic resolution • Kinetic analysis provides insight into reaction pathways Density Functional Theory calculations are used to determine the thermodynamics and kinetics of proposed reaction mechanisms
•
Graduate Student Haojuan Wei has identified novel acrolein hydrogenation catalysts based on dilute alloys
•
Graduate student Carolina Gomez has found that alloying effects in XAS can be classified in terms of charge transfer, lattice effects and changes in orbital overlap.
•
Graduate student David Childers has shown that alloy catalysts for neopentane hydrogenolysis/isomerization can be more selective than either monometallic component.
Sohail Murad, Chemical Engineering Department Primary Grant Support: US National Science Foundation
Problem Statement and Motivation FAU Zeolite
MFI Zeolite
CHA Zeolite
•
Understand The Molecular Basis For Membrane Based Gas Separations
•
Explain At The Fundamental Molecular Level Why Membranes Allow Certain Gases To Permeate Faster than Others
•
Use This Information To Develop Strategies For Better Design Of Membrane Based Gas Separation Processes For New Applications.
y z
Zeolite Membrane x
Feed Compartment (High Pressure)
Product Compartment (Low Pressure)
Feed Compartment (High Pressure)
Recycling Regions
Key Achievements and Future Goals
Technical Approach •
Determine The Key Parameters/Properties Of The Membrane That Influence The Separation Efficiency
•
Explained The Molecular Basis Of Separation of N2/O2 and N2/CO2 Mixtures Using a Range of Zeolite Membranes.
•
Use Molecular Simulations To Model The Transport Of Gases –i.e. Diffusion or Adsorption
•
Used This Improved Understanding To Predict Which Membranes Would Be Effective In Separating a Given Mixture
•
Focus All Design Efforts On These Key Specifications To Improve The Design Of Membranes.
•
Used Molecular Simulation to Explain the Separation Mechanism in Zeolite Membranes.
•
Use Molecular Simulations As A Quick Screening Tool For Determining The Suitability Of A Membrane For A Proposed New Separation Problem
Huajun Yuan, Cynthia Jameson and Sohail Murad Primary Grant Support: National Science Foundation, Dow Chemical Company
Problem Statement and Motivation •
Needs for Better Physical Property Model
•
Industrial Interest – Safe Storage of Liquids at Extreme Conditions
•
Understand Molecular Basis For Chemical Shift in Liquids
•
Explain At the Fundamental Molecular Level the Close Relation Between Chemical Shift and Solute-Solvent Interaction Potential
•
Use This Information to Develop Strategies For Better Design of Solute-Solvent Interaction Potentials, and Provide a Better Estimation of Henry’s Constant (Solubility of Gases in Liquids)
Key Achievements and Future Goals
Technical Approach •
Use Molecular Dynamics Simulation to Model Chemical Shift of Gases in Alkanes
•
Determined the Key Parameters of Solute-Solvent Interaction Potential, Improved the Potential for Better Solubility Estimations.
•
Determine the Key Parameters of Solute-Solvent Interaction Potential.which Affect the Solubility
•
Calculated the Gas Solubility of Xenon in Different Alkanes at Different Temperatures. Showed that Improved Agreement with Chemical Shift Resulted In Better Solubility Results
•
Use Molecular Simulation for Chemical Shift Calculation as a Quick Screening Tool for Improving the Intermolecular Potential.
•
Able to Use Modified Potential Model to Get Better Estimations of Solubility of Gases In Liquids, Especially under Extreme Conditions Which are Difficult to Measure Experimentally.
•
Estimate the Solubility of Gases in Liquids using the Improved Potential Model.
Lewis E. Wedgewood, Chemical Engineering Department Primary Grant Support: National Science Foundation, 3M Company
Problem Statement and Motivation •
Construct a Theory that Allows the Vorticity to be Divided into an Objective and a Non-Objective Portion
•
Develop Robust Equations for the Mechanical Properties (Constitutive Equations) of Non-Newtonian Fluids using the Objective Portion of the Vorticity
•
Solve Flow Problems of Complex Fluids in Complex Flows such as Blood Flow, Ink Jets, Polymer Coatings, Etc.
Key Achievements and Future Goals
Technical Approach •
Mathematical Construction of Co-rotating Frames (see Figure above) to Give a Evolution for the Deformational Vorticity (Objective Portion)
•
Finite Difference Solution to Tangential Flow in an Eccentric Cylinder Device
•
Brownian Dynamics Simulations of Polymer Flow and Relation Between Polymer Dynamics and Constitutive Equations
•
Continuum Theory And Hindered Rotation Models To Model Mechanical Behavior
•
Improved Understanding Of the Modeling of Complex Fluids
•
Applications to Structured Fluids such as Polymer Melts, Ferromagnetic Fluids, Liquid Crystals, etc.
•
Development Of Constitutive Relations Suitable For Design Of New Applications
•
Verification Of Hindered Rotation Theory And The Transport Of Angular Momentum In Complex Fluids