本项目拟将弦方法引入高分子的自洽平均场理论，以期研究相变的最小自由能路径、亚稳态的生成及对路径的依赖性、新相在老相中如何孕育或成核直到最终形成等基本相变问题，发展分析有序-有序相结构转变的动力学方法。通过设计弦的初始状态，考察成核-增长相变中的临界核尺寸、形状及位垒等成核信息，以及相变间的外延生长关系；扫描spinodal相变路径中的各个亚稳态，分析其生成及稳定性。发展处理复杂拓扑链结构及半刚性高分子取向的高效数值算法，实现对高维空间中复杂球状、多连续网状以及含有液晶相结构的动力学形成路径的设计与调控。所发展的理论方法将有助于理解高分子多连续网状及液晶结构中的相转变路径及动力学行为，为具有精密介观相结构的高性能及功能材料的设计与制备提供理论指导。

By applying the string method to the self-consistent field theory in the polymeric system, this project aims to develop effective methods to investigate order-order phase transition kinetics, including the minimum energy pathways, the emergence of various metastable states and their dependence on these pathways as well as the nucleation and growth of the new phases within the old ones. We focus on studying the epitaxial relationship between distinct phases, the nucleation details such as the shape, size of the critical nucleus and the nucleation barrier, as well as the development and stability of the metastable states during spinodal decomposition, by designing different initialization procedures of the string. Furthermore, we develop effective numerical algorithms to deal with molecular chains with complex topology and chain rigidity. In this way, we expect to realize the design and regulation of the kinetic pathways to complex spherical packing phases, multiply continuous networks and complex mesophases with liquid crystal orientation effect. The developed theoretical method is expected to understand the phase transition pathways and kinetics regarding complex self-assembled networks and liquid crystals, thus providing guidance for the design and fabrication of high performace and functional materials.