高分子液晶体系分子尺度机制的理论研究

The research field of liquid crystalline polymers is one of the most important branches of polymer science. These systems have excellent physical properties under high tensile strength and respond extraordinarily well to external photoelectric stimulates. As such they have been extensively applied in many application fields, such as elastic fibers, polymeric nanocomposites, information storage, and visual display. Theoretical research of this topic thus has important significance in practical applications. The orientational interactions between mesogenic units usually lead to the local alignment of molecules along one direction. At the same time, the linkage of the polymer chains forms microstructures that display specific symmetris in space. These hierarchical structures, as the result of polymer self-assembly in space and liquid-crystal ordering in orientation, play crucial roles in determining the physical properties of liquid crystalline polymers. This proposal suggests to adopt the self-consistent field theory (SCFT) based on the wormlike chain model, in order to explore the physical mechanisms on the basis of molecular-level parameterization. The new aspects include considerations of the variation of polymer-chain configurations, orientational interaction between mesogenic units, and molecular alignments induced by the surface curvature. The study is expected to provide a fundamental explanation for the semi-phenomenological parameters used in other theories, by using the molecular-scale physical parameters and to explore the inner correlation between phenomenological theories and coarse-grained models. At the same time, the study aims at providing a theoretical foundation for the fabrication of complex and controllable mesostructures formed by liquid crystalline polymers in experiments.

高分子液晶是高分子研究领域中的重要分支，因其具有定向高拉伸强度、对外界光电作用特定响应模式等方面的卓越性能，被广泛应用于弹性纤维、高分子复合材料、信息存储、光学显示等众多领域，因此，在理论研究和实际应用中都具有重要意义。由于液晶基元间的取向相互作用，高分子液晶在局域呈现出取向有序排列，同时，由于高分子链的键合作用，其将形成具有特定对称性的空间结构，这种空间堆积和取向排列耦合的多级次自组装微结构对于高分子液晶的性能起着决定性的作用。本项目拟采用基于蠕虫状链模型的自洽场方法，深入探讨高分子链构象变化、液晶基元间的取向相互作用、曲率界面对液晶高分子的取向诱导作用等多因素耦合情况下形成多级次结构在近分子尺度上的物理机制，寻找唯像理论中选取的经验参数在分子尺度上的物理解释，探索唯像理论模型与粗粒化分子尺度模型之间的内在关联性，为实验制备纳微尺度的复杂、可控高分子液晶微结构提供参考和理论指导。

课题围绕高分子液晶体系的分子尺度机制展开研究，高分子液晶具有定向高拉伸强度、对外界光电作用特定响应模式等方面的卓越性能，被广泛应用于弹性纤维、高分子复合材料、信息存储、光学显示等众多领域，在理论研究和实际应用中都具有重要意义。项目采用Onsager模型和Landau-de Gennes模型等不同理论模型，结合自洽场方法、机器学习等算法优化，深入探讨受限条件下的高分子链构象变化、液晶基元间的取向相互作用、曲率界面对液晶高分子的取向诱导作用等多因素耦合情况下形成多级次结构在近分子尺度上的物理机制，寻找唯像理论中选取的经验参数在分子尺度上的物理解释，探索唯像理论模型与粗粒化分子尺度模型之间的内在关联性，为实验制备纳微尺度的复杂、可控高分子液晶微结构提供参考和理论指导。