Light Scattering, Rheo-Optical, and Rheological Studies on Concentrated Polymer Solutions

本研究包括四个不同的研究领域：(1)棒状聚合物的排列向列溶液的静态和动态光散射，以及相同溶液的排列和非排列向列溶液的流变学和流变光学研究；(2)热致性共聚物的向列相作为温度函数的类似研究；(3)聚苯乙烯中等浓度溶液在十氢化萘中的静态、动态光散射及流变性研究；(4)易发生分子间缔合的聚合物稀溶液的静态和动态光散射。在第一项研究中，莱斯利粘度、弗兰克曲率弹性和有序参数将在链长和聚合物浓度的范围内确定。这些参数也将用于分析材料在快速流动中的非线性流变行为。其次，将进行初步研究，以评估散射研究的可行性，以确定无溶剂排列向列相聚合物上的某些莱斯利粘度和弗兰克弹性。第三，热力学和链动力学将在一系列条件下进行研究，从Flory Theta状态到“良好的溶剂”条件。由于链缠结引起的动态散射中的松弛现象将引起特别的兴趣。最后，在第四章中，将研究稀溶液中某些热致变色效应与（亚稳态）分子间结合有关的可能性。本研究旨在阐明各种类型的重要聚合物的溶液行为，特别是那些能够形成液晶的聚合物。

This study comprises four distinct areas of investigation: (1) Static and dynamic light scattering on aligned nematic solutions of a rodlike polymer, and rheological and rheo-optical studies on aligned and unaligned nematic solutions of the same solutions; (2) Similar studies on the nematic phase of a thermotropic copolymer, as a function of temperature; (3) Static and dynamic light scattering, and rheological studies on moderately concentrated solutions of polystyrene in decalin; and (4) Static and dynamic light scattering on dilute solutions of polymers prone to intermolecular association. In the first study, the Leslie viscosities, the Frank curvature elasticities, and the order parameter will be determined over a range of chain length and polymer concentration. These parameters will also be used in the analysis of nonlinear rheological behavior in fast flow behavior. In the second, a preliminary study will be undertaken to evaluate the feasibility of the scattering studies to determine certain Leslie viscosities and Frank elasticities on a solvent-free aligned nematic polymer. In the third, the thermodynamics and chain dynamics will be studied over a range of conditions, from the Flory Theta state to "good solvent" conditions. The appearance of relaxation in the dynamic scattering due to chain entanglements will be of special interest. Finally, in the fourth, the possibility that certain thermochromic effects in dilute solution are linked to (metastable) intermolecular association will be investigated. This research aims to clarify the solution behavior of various types of important polymers, especially those able to form liquid crystals.