last update: March 28, 2001
|
STC-ERSP Program Details Principal Investigator: Michael Rubinstein Project Title: Models of Polymeric Surfactants (#10) Phone/Fax: (919)-962-3544/(919)-962-9312 E-mail: mr@unc.edu Research Plan Connectivity Requested Budget Allocation - Year 1 Research Plan Overall objectives Rubinstein proposes to develop theoretical and computer models for polymer self-assembly in highly compressible solvents (e.g. liquid and supercritical CO2). A systematic study of the effects of CO2 -phobic and CO2 - philic interactions will allow us to understand the key processes governing the phase separation and micelle formation. We will investigate the thermodynamic properties of block copolymer self-assembly as a function of material variables and CO2 pressure and temperature. Relation to overall objectives of the Center The theoretical and computer models will lead to detail understanding the relevant mechanisms controlling self-assembly of polymeric surfactants in compressible fluids. This research will expand the use of surfactant-modified CO2 in a wide range of manufacturing processes. Approach and Year 1-Year 5 timelines Years 1-2: We will develop theoretical models to describe the thermodynamic principle of self-assembly in dilute polymer solutions. We will focus on the molecular parameters controlling the geometry of micelles. Of special interest are the boundaries between spherical micelles, cylindrical micelles, and bi-layers. The goal is to be able to change the geometry of micelles (say from spherical to cylindrical) by changing solvent quality (pressure or temperature of CO2). This will dramatically change physical properties (e.g. viscosity) of the system. We will also develop computer models to describe the properties of polymers in compressible solvents (solubility, chain conformations). Years 2-3: Computer models will be extended to study self-assembly of block copolymers in liquid and supercritical CO2. We will simulate micelles with different aggregation number in order to find out the optimal shape and size of these aggregates. Our study will also produce phase diagrams of block copolymers as functions of the polymer concentration, polymer molecular weight, strength of the of CO2-phobic and CO2-philic interactions, polymer architecture, CO2 pressure and temperature. Years 3-5: We will extend theoretical and computer models to describe multi-component systems like CO2/oil/surfactant mixtures and CO2/water/surfactant mixtures. We will calculate phase diagrams of these mixtures. Thrust area of this proposal Thrust Area B : Molecular Dynamics and Computer Simulation Connectivity Collaborators, multi-institutional, multi-disciplinary components Computer simulations will be carried out in collaboration with Berkowitz (UNC-CH). Related work in other thrust areas Complimentary experiments on homopolymers, block copolymers and the mixtures will be carried out in Thrust Area A (Interfacial and Colloidal Science in Compressible Media) by DeSimone (UNC-CH) and M. Adam (Paris, France). Sharing of resources (students, supplies, equipment, etc.) The computer system used for numerical simulations will be shared with Berkowitz (UNC-CH). Requested Budget Allocation - Year 1 Personnel salaries
|
|
