应用微观动力学新模型研究高分子结晶机理

高分子结晶经过几十年的研究，仍有一些关键问题尚未解决，譬如成核、生长和熔化的微观机制，中间态性质随尺寸的变化等。本申请拟采用理论和实验相结合的研究思路，通过建立结晶新模型来推测高分子结晶的微观机理，然后设计实验检验理论预测。这一高分子结晶新模型，基于可逆吸附-脱附的微观动力学框架，通过微观动力学速率常数随中间态尺寸的变化，可描述不同中间态的竞争性生长。新模型的关键和创新之处，是以多体关联参数为桥梁，建立高分子结晶动力学、宏观结构参数及热力学量和微观动力学参数的定量关系。拟采用Matlab和Monte Carlo等方法模拟高分子结晶成核、生长和熔化的动态演化过程。以理论推论为基础，进一步设计实验检验模型预测，研究并尝试解决高分子结晶厚度的选择原则，结晶成核、片晶增厚和熔融的微观机制，中间态的性质，高分子和小分子结晶的异同等问题。通过本项目的研究，有望发展高分子结晶理论，形成原创性成果。

Though polymer crystallization has been intensively studied for decades, there are still some important questions remain open, such as microscopic mechanism of nucleation, existence of mesophase or not and variation of properties of crystal embryos with size, etc. In this proposal, we attempt to solve these challenges via the following strategy: First, a new model for polymer crystallization will be established, based on microscopic kinetics of attaching and detaching. The key of the model is the multibody-interaction parameters that correlate the macroscopic properties, such as energy barrier, surface free energy and lamellar thickness, to the microscopic kinetics parameters. Matlab and Monte Carlo methods will be applied to simulate the evolution of polymer lamellae so as to reveal the microscopic mechanism of nucleation, lamellar thickening and melting. Second, the corresponding experiments will be designed to study the variation of lamellar thickness with temperature, the properties of the mesophase, and the difference between small molecule and polymer crystallization. The research is expected to develop a new theory on polymer crystallization and deepen our understanding of crystallization.