Structure and Dynamics of Network Janctions in Thermoreversible Gels of Associating Polymers

本项目研究了具有多个交联结的缔合聚合物的三可逆凝胶化。我们特别关注了(1)网络结的多样性和序列长度，(2)网络结的运动和弹性有效链的数量，(3)分子间胶束化和分子间交联的竞争，(4)添加表面活性剂的影响，(5)聚合物构象变化和凝胶化的协同效应，(6)混合网络的形成。我们得到了完整的相图，包括相分离、凝胶化、胶束化、微相分离等。将传统的Eldridge-Ferry方法扩展到交联反应的多重性和焓值，并应用于聚乙烯醇在水中的凝胶熔化曲线。在存在稳定交联所需的最小复数的假设下，研究了添加表面活性剂对疏水改性聚合物溶液中可逆凝胶形成的影响。对于远螺旋缔合聚合物，我们发现了在凝胶点之前出现花胶束（仅由环形成的胶束）的条件。

This project studied thremoreversible gelation of associating polymers with multiple cross-link junctions. We paid special attention to (1) the multiplicity and sequence length of the network junctions, (2) motion of network junctions and the number of elastically effective chains, (3) competition between intermolecular micellization and intermolecular cross-linking, (4) effect of added surfactants, (5) cooperative effect of conformational change of polymers and gelation, (6) formation of mixed networks. We derived complete phase diagrams including phase separation, gelation, micellization, microphase separation etc. The conventional Eldridge-Ferry method is extended to evaluate multiplicity, as well as enthalpy, of the cross-links, and applied to the experimental gel melting curves of poly (vinyl alcohol) in water. The effect of added surfactants on the formation of reversible gels in hydrophobically modified polymer solutions is also studied under the assumption of the existence of a minimum multiplicity required for stable cross-links. For telechelic associating polymers, we found the condition for appearance of flower micelles (micelles formed only by loops) before the gel point.