二元分子体系在过冷液态与玻璃态中二级（beta）弛豫动力学的常压与高压研究

项目名称： 二元分子体系在过冷液态与玻璃态中二级（beta）弛豫动力学的常压与高压研究

项目编号： No.11474247

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 王利民

作者单位： 燕山大学

项目金额： 80万元

中文摘要： beta弛豫广泛存在于各类玻璃态材料中，不断增加的证据表明该动力学与玻璃态材料中的众多性质密切相关，包括稳定性与变形机制等。对beta弛豫的深入理解将为更有效地优化玻璃态材料的性能提供新的思路。目前对于beta弛豫物理本质的认识仍不清楚，与其对应的结构起源尚不清楚。本项目中，我们提出：选择具有多种混合特征的二元小分子体系作为研究对象，结合高压手段开展液态与玻璃态中beta弛豫动力学研究。计划采用多种方式建立beta弛豫与微观结构变化之间的对应关系。通过调控混合热与混合体积系统改变二元体系玻璃态的微结构，探索不同混合模式下的beta弛豫特征。利用常压与高压下的介电弛豫技术分析二元体系中beta弛豫与分子体积较大和较小组元运动之间的相关性。利用焓弛豫技术建立beta弛豫与热力学的关联，进一步理解该动力学的微结构起源。项目的开展将为最终理解beta弛豫的物理本质提供新的参考。

中文关键词： 玻璃化转变；介电弛豫；过冷液体

英文摘要： There is increasing experimental evidence that beta-relaxations present in various glassy materials correlate closely with other properties of materials such as the thermal stability and deformation mechanisms. It is certain that the development of the understanding of the beta-relaxation dynamics would benefit the optimization of the properties in glassy materials. Yet, the physical origin of the beta-relaxations remains to be clarified. Specifically, the understanding of the microscopic structural correlation of the dynamics has not been commonly recognized. In this project, we propose an idea to explore the problem by focusing on the binary molecular systems of multiple mixing modes imposed by the modification of heat of mixing and volume of mixing. The conventional and high-pressure dielectric relaxation and enthalpy relaxation are used. Distinct experiments designed to demonstrate the effect of the microstructural modification on the beta-relaxation dynamics are performed to unveil the dynamic characters of the beta-relaxations in binary mixtures with diverse mixing modes. High pressure dielectric relaxations will be used in search of the relation of the beta-relaxation to both large and small constituents in binary glassy mixtures. The understanding of the microstructural origin of the beta-relaxation will be further developed by characterizing the thermodynamics of the beta-relaxations, where enthalpy relaxation measurements are involved. The studies are expected to offer new references to the ultimate interpretation of the beta-relaxation physics.

英文关键词： glass transition;dielectric relaxation;supercooled liquids