Molecular Motions in Supercooled Liquids

威斯康星大学麦迪逊分校的Mark Ediger教授由理论和计算化学项目支持，对过冷液体的结构和动力学以及玻璃/液体转变进行热力学研究。PI使用中子前向反冲光谱和中子反射率来评估氚分子和非氚分子的薄双层样品中的自扩散。样品包括甘油、碳酸亚丙酯和水等形成玻璃的小分子。其次，一种新的固体核磁共振方法正被用于提供作为温度函数的结构信息的几种过冷液体和薄膜。新类型的数据将为预测凝聚相中的相变提供重要的理论依据。尽管过冷液体的面积和玻璃/液体相变的历史很长，但在相变点附近分子运动的性质和结构对玻璃形成材料性能的影响方面，仍有许多基本问题没有得到解答。对玻璃态的更好理解将对包括聚合物科学在内的材料应用产生影响。

Professor Mark Ediger of the University of Wisconsin Madison is supported by the Theoretical and Computational Chemistry program to perform thermodynamic studies of the structure and dynamics of supercooled liquids and the glass/liquid transition. The PI uses neutron forward recoil spectrometry and neutron reflectivity to assess self-diffusion in thin bilayer samples of deuterated and nondeuterated molecules. Samples include small polar glass forming molecules such as glycerol, propylene carbonate and water. Secondly, a solid state NMR method new to this application is being used on several supercooled liquids and films providing structural information as a function of temperature. New types of data will provide important benchmarks for theoretical efforts in predicting phase transitions in condensed phases.Despite having a long history, the area of supercooled liquids and the glass/liquid transition has many fundamental unanswered questions about the nature of molecular motions near the transition point and the influence of structure on properties of glass forming materials. An improved understanding of the glassy state will have impact on materials applications including polymer science.