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

这项研究包括四个不同的研究领域：(1)棒状聚合物取向向列相溶液的静态和动态光散射，以及同一溶液的取向和未取向向列相溶液的流变学和流变学研究：(2)热致共聚物向列相的类似研究，作为温度的函数；(3)静态和动态光散射，以及中等浓度聚苯乙烯十氢呋喃溶液的流变学研究；(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。在第一个研究中，Leslie粘度、Frank曲率弹性和有序参数将在一定的链长和聚合物浓度范围内确定。这些参数也将用于分析快速流动状态下的非线性流变行为。在第二项研究中，将进行初步研究，以评估散射研究的可行性，以确定无溶剂取向向列聚合物上的某些Leslie粘度和Frank弹性。在第三章中，我们将在一系列条件下研究热力学和链动力学，从Flory Theta状态到“良好溶剂”条件。由链纠缠引起的动态散射中的弛豫现象将会引起人们的特别关注。最后，在第四章中，我们将探讨稀溶液中某些热致变色效应与(亚稳态)分子间缔合的可能性。这项研究旨在阐明各种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.