Thermodiffusion of ternary polymer solutions

三元混合物是真正多组分系统的原型，因为它们表现出二元混合物中仍然没有的特征交叉耦合现象。我们想研究含有至少一种聚合物组分的三元混合物中的热扩散。通过对聚合物在混合溶剂中的研究，研究了溶剂-溶剂的耦合解耦和聚合物-溶剂动力学。通过增加聚合物的摩尔质量，我们将能够研究由大小相似的分子组成的相称的三元混合物向成分尺寸明显不对称的不相称体系的转变。基于设想的实验，基于我们之前关于热疏性概念的工作，以及二元聚合物溶液和混合物的结果，我们将把热疏性模型扩展到三元混合物，并研究一种有效的溶剂方法在混合溶剂中的聚合物的可行性。我们还将在混合溶剂中建立聚合物作为三元液体的完全可表征的模型系统。与小分子混合物相反，可以预期扩散矩阵的特征值的明确分离，这将允许对非等温三元混合物的所有六个独立扩散输运系数进行独特的确定。实验工作将通过与K. Morozov （Technion Haifa）的密切合作来补充理论方面的工作，他将使用PC-SAFT状态方程和项目实验部分的数据，将他现有的硬球体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.