高分子玻璃化熵理论研究进展

Advances in the generalized entropy theory of polymer glass formation

玻璃化问题的理论描述是凝聚态物理中的重要基础科学研究课题.高分子是研究玻璃化的典型模型体系,其独有的分子特征为发展有效、普适的玻璃化理论提供了新的机遇.构型熵是发展玻璃化理论的一个核心物理量.基于构型熵的模型可追溯至近一个世纪前观察到的熵与动力学关联的实验现象,并且近年来该理论的发展进入了一个新的阶段,特别是在高分子玻璃化的研究中.本文首先对玻璃化经典熵理论的发展进行了回顾,并介绍了高分子玻璃化熵理论的基本框架.之后,从分子细节影响高分子玻璃化的物理机制、热力学标度与活化体积的理论描述和高分子过冷液体的热力学-动力学关系三个方面阐述了本课题组近年来基于高分子玻璃化熵理论的研究进展,重点强调了该理论在理解高分子玻璃化关键问题中的价值和优势.最后,探讨了高分子玻璃化熵理论进一步发展面临的问题与挑战,并且对玻璃化理论研究的未来发展方向进行了展望.

The theoretical description of glass formation remains an important fundamental problem in condensed matter physics.Polymers have been a prototypical model to study glass formation,and their unique molecular characteristics provide a set of powerful constraints on the development of generally valid and broadly applicable approaches to glass formation.Configurational entropy has been a key quantity in the development of theoretical approaches to glass formation.The configurational entropy-based models can be traced back to the experimental observations of correlations between the fluid entropy and liquid dynamics nearly a century ago,and the development of these approaches has entered a new phase in recent years,especially in the study of polymer glass formation.The present review begins with a brief summary of classical entropy theories,followed by an introduction to the generalized entropy theory(GET)of polymer glass formation.Recent advances are then described in our studies of polymer glass formation based on the GET,with a particular focus on the physical mechanism of the dependence of polymer glass formation on molecular factors,the theoretical description of activation volume and thermodynamic scaling,and the thermodynamic-dynamic interrelations of glass-forming polymer fluids.The emphasis is placed on the power and unique capacity of the GET in investigating the key problems related to glass formation.Finally,the challenges and opportunities are discussed regarding the further development of the GET,along with remarks on several key topics in the theoretical study of glass formation.