Single Molecule Studies of Molecular Motions Near the Glass Transition

该项目由化学部实验物理化学项目资助，研究材料玻璃化转变附近的空间异质性。嵌入在感兴趣的系统中的单探针分子的荧光将用于直接表征非均相环境。这项工作将解决三个主要问题：1)非均质性如何在不同的长度尺度上表现出来？2)非均质性与玻璃的脆性是如何相关的？3)相邻非均质区域的动力学是否相关？聚苯乙烯和甘油将是主要的玻璃形成物，其中嵌入了不同大小的探针分子。参与这项研究的学生将在当代物理化学领域获得宝贵的经验，这将为他们在学术、政府或经济工业部门的进一步学习或就业做好准备。

This project, funded by the Experimental Physical Chemistry Program of the Chemistry Division, deals with the spatial heterogeneities in materials near their glass transition. The fluorescence of single probe molecules embedded in the system of interest will be used for the direct characterization of the heterogeneous environments. Three main issues will be addressed in this work: 1) How does heterogeneity manifest itself on different length scales? 2) How is the heterogeneity related to the fragility of the glass former? 3) Are the dynamics in neighboring heterogeneous regions correlated? Polystyrene and glycerol will be the principal glass-formers in which probe molecules of different sizes are embedded. The students who participate in this research will gain valuable experience in a contemporary area of physical chemistry that will prepare them for further study or employment in the academic, government or industrial sectors of the economy.