Morphological characterization of polymer solutions and blends undergoing phase separation

该拟议的研究计划是申请人正在进行的研究的一部分，该研究通过数学建模和计算机模拟，在聚合物溶液和共混物中通过旋节线分解进行相分离，以形成功能性聚合物材料。 相分离的聚合物溶液和共混物的应用发现于：（1）用于分离过程的聚合物膜，（2）用于电光器件的聚合物分散液晶膜，和（3）用于需要上级机械性能的目的的工程聚合物复合材料。 这些应用主要依赖于相分离聚合物体系的非均匀形态。 我们的研究结果可用于设计，制造和控制的工程功能聚合物复合材料的空间非均匀形态。 这个拟议的研究计划的总体目标是发展的形态演变的聚合物溶液和共混物通过spinodal分解进行相分离的基本理解。 具体目标是：（1）建模、模拟和表征在浓度梯度存在下经历聚合诱导相分离的聚合物溶液和共混物的形态，（2）建模、模拟和表征经历顺序骤冷进入相图的亚稳和不稳定区域的聚合物溶液和共混物的形态，和（3）确定Ludwig-Soret（即，热扩散）现象的聚合物溶液和共混物的数学建模和计算机模拟。 该模型将包括相分离的Cahn-Hilliard理论和聚合物热力学的Flory-Huggins理论。 该模型将使用有限差分和Galerkin有限元法进行数值求解。 数值结果将使用科学可视化进行处理，以便模型和数值结果可以与实验结果进行验证。 将通过计算结构因子并结合数字图像分析使用科学可视化来表征形态学。

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.