Morphological characterization of polymer solutions and blends undergoing phase separation

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This proposed research program is part of the ongoing research that the applicant is pursuing on phase separation via spinodal decomposition in polymer solutions and blends to form functional polymeric materials through mathematical modeling and computer simulation.  Applications of phase-separated polymer solutions and blends are found in: (1) polymer membranes for separation processes, (2) polymer dispersed liquid crystal films for electro-optic devices, and (3) engineering polymer composite materials for purposes that require superior mechanical properties.  These applications depend primary on the nonhomogenous morphology of the phase-separated polymer systems.  Our results may be used in the design, manufacture and control of engineering functional polymeric composite materials with spatially nonhomogenous morphologies.    The overall objective of this proposed research program is to develop a fundamental understanding of the morphological evolution of polymer solutions and blends undergoing phase separation via spinodal decomposition.  The specific objectives are: (1) to model, simulate and characterize the morphology of polymer solutions and blends undergoing polymerization-induced phase separation in the presence of a concentration gradient, (2) to model, simulate and characterize the morphology of polymer solutions and blends undergoing sequential quenching into the metastable and unstable regions of the phase diagram, and (3) to determine the effect of the Ludwig-Soret (i.e., thermal diffusion) phenomenon in polymer solutions and blends using mathematical modeling and computer simulation.    The model will consist of the Cahn-Hilliard theory for phase separation and Flory-Huggins theory for polymer thermodynamics.  The model will be solved numerically using finite difference and Galerkin finite element methods.  The numerical results will be processed using scientific visualization so that the models and numerical results can be validated with experimental results.  The morphology will be characterized by computing the structure factor and using scientific visualization in conjunction with digital image analysis.