Thermodiffusion of ternary polymer solutions

三元混合物是真正的多组分体系的原型，因为它们表现出二元混合物中仍然不存在的特征交叉耦合现象。我们想研究至少含有一种聚合物组分的三元混合物中的热扩散。通过研究混合溶剂中的聚合物，我们希望研究溶剂-溶剂的耦合和解耦以及聚合物-溶剂动力学。通过增加聚合物的摩尔质量，我们将能够研究从一个相称的三元混合物，由类似大小的分子，一个不相称的系统与一个明显的大小不对称的成分组成的过渡。基于设想的实验，我们以前的工作的热疏概念，和二元聚合物溶液和共混物的结果，我们将扩展的热疏模型的三元混合物和研究的可行性的有效的溶剂方法的聚合物在混合溶剂中。我们还将建立混合溶剂中的聚合物作为三元液体的充分表征模型系统。相反的小分子的混合物，扩散矩阵的本征值的一个明确的分离，可以预期，这将允许一个独特的确定所有六个独立的扩散传输系数的非等温三元混合物。实验工作将通过与K. Morozov（Technion Haifa），他将使用PC-SAFT状态方程和该项目实验部分的数据，将他现有的硬球模型扩展到柔性链分子和三元混合物。

Ternary mixtures are prototypic for truly multicomponent systems, since they show characteristic cross coupling phenomena that are still absent in binary mixtures. We want to investigate thermodiffusion in ternary mixtures containing at least one polymeric component. By studying a polymer in a mixed solvent we want to investigate the coupling and decoupling of the solvent-solvent and the polymer-solvent dynamics. By increasing the molar mass of the polymer we will be able to study the transition from a commensurate ternary mixture, composed of similar-sized molecules, to an incommensurate system with a pronounced size asymmetry of the constituents. Based on the envisaged experiments, on our previous work on the thermophobicity concept, and on results for binary polymer solutions and blends, we will extend the thermophobicity model to ternary mixtures and investigate the feasibility of an effective solvent approach for a polymer in a mixed solvent. We will also establish polymers in mixed solvents as fully characterizable model systems for ternary liquids. Contrary to mixtures of small molecules, a clear separation of the eigenvalues of the diffusion matrix can be expected, which will allow for a unique determination of all six independent diffusive transport coefficients of a non-isothermal ternary mixture. The experimental work will be complemented on the theoretical side by an intense collaboration with K. Morozov (Technion Haifa), who will extend his existing model for hard spheres to flexible chain molecules and ternary mixtures using the PC-SAFT equation of state and data from the experimental part of the project.