分子模拟在聚酰亚胺研究中的应用

Application of Molecular Simulation in the Study of Polyimide

聚酰亚胺(PI)是一类通过酰亚胺键连接的环链状高分子聚合物,其化学组成可调,同时具有复杂的多尺度多层次结构特征,更进一步地影响了材料的热学、力学和光电性能.本文综述了近年来分子模拟方法在PI中的应用,辅助研究和解释了PI材料的结构和性能的关系.结构上,包括分子链结构、凝聚态的结晶、取向结构、自由体积以及相结构;性能上,介绍了分子模拟在PI材料热性能、机械性能、气体分离以及PI基复合材料的界面结合性能方面的应用.最后,对计算机模拟在聚酰亚胺研究中的发展趋势进行了展望,本文对于PI性能优化和功能性PI的设计制备具有一定的理论指导意义.

Featured by its outstanding thermo-oxidative stability and excellent mechanical properties, polyimide has aroused growing research interests. The hierarchical structure of polyimide(PI), which largely influences its thermal, mechanical, and photoelectric properties, can be well adjusted by carefully regulating the chemical composition. In this review, we primarily focus on the employment of molecular simulation for unravelling and interpreting the structure-property relationship of PI materials, and summarize the recent progress both at home and aboard on the research of multi-scale PI structures. The molecular chain structures of PI can be finely analyzed in terms of the chains conformation, characteristic ratio and torsion energy barrier, while the thermal and mechanical properties are properly explained from the perspective of molecular chain constitutions, chains movement and the packing state of PI chains. Meanwhile, the highly concerned force field has been used in molecular dynamic(MD) simulation of PI thermal-mechanical behaviours. MD simulation or Monte Carlo(MC)simulation also works well for understanding the gas separation performance of PI materials through the fractional free volume(FFV) of PI molecules or the dissolution and diffusion patterns of small molecules in novel PI framework with particular main-chain or side-chain structures. Furthermore, the studies on PI-based composites are basically concentrated on the exploration of interfacial properties between PI and other materials, including the simulated binding energy and small-scale interactions like the van der Waals forces and electrostatic interactions.The development trend of computer simulation in PI-related research is briefly discussed in the end, so as to provide valuable guidance for the performance optimization of PI materials as well as some useful thoughts on the design and preparation of functional PI molecules.