GHz-THz Dynamics and the Glass Transition in Polymers

了解分子运动的基本原理对于理解从宏观到纳米尺度的聚合物的许多性质是至关重要的。在聚合物动力学的各个方面中，GHz-THz频率范围的动力学值得特别关注，因为它在信息和通信技术以及光子学中的应用具有重要意义。本程序研究了聚合物体系从固态到液态的宽温度范围内的GHz-THz动力学。采用了三种实验技术：光、中子散射和介电弛豫谱。这一组合提供了有关快速动力学的详细微观信息，并有助于了解其与聚合物宏观性质的关系。这一计划将促进对聚合物材料GHz-THz特性背后的微观机制和纳米尺度上的分子运动的理解。这将为新的理论方法的发展创造坚实的实验基础。预期的结果将对聚合物科学、对复杂系统的动力学、材料科学和一般物理学以及通过更好地了解生物聚合物动力学而对生物物理学产生重大影响。该计划包括与美国和欧洲的几个小组进行广泛的合作。GHz-THz动力学的高级知识对当前和未来通信、信息和计算技术的材料设计和合成、光子应用材料的开发以及一些生物技术的进步具有重大影响。拟议的计划还通过研究生和本科生积极参与这项研究、研究生课程的开发，对未来技术专业人员的教育产生了重大影响。建议方向的进展将影响材料科学、物理和生物物理的各个领域。拟议的计划促进了与NIST和ANL的国家多用户设施的积极国际合作和协作。***

Understanding the fundamentals of molecular motions is crucial for understanding many properties of polymers from macro- to nano- scale. Among various aspects of polymer dynamics the dynamics in the GHz-THz frequency range deserves particular attention because of its importance for applications in information and communication technologies and in photonics. The GHz-THz dynamics of polymeric systems in a broad temperature range, from deep in a solid state up to deep in a liquid state, is studied in this program. Three experimental techniques, light and neutron scattering and dielectric relaxation spectroscopy, are employed. This combination provides detailed microscopic information on the fast dynamics and helps to understand its relationship with macroscopic properties of polymers. This program will advance understanding of microscopic mechanisms behind GHz-THz properties of polymeric materials and molecular motions on a nanometer scale. It will create a solid experimental basis for developments of new theoretical approaches. Expected results will have significant implications on polymer science, and in broader aspect on dynamics of complex systems, Materials Science and Physics in general, and also on Biophysics through better understanding of bio-polymers dynamics. The program includes broad collaborations with a few groups in the US and in Europe.%%%Advanced knowledge of the GHz-THz dynamics has significant impact on design and synthesis of materials for current and future communication, information and computation technologies, on developments of materials for photonic applications, and on a progress in some bio-technologies. The proposed program has also significant impact on education of specialists for future technologies through active involvement of graduate and undergraduate students in this research, developments of graduate courses. Advances in the proposed directions will impact various fields of Materials Science, Physics and Biophysics. The proposed program promotes active international cooperation and collaboration with national multi-user facilities at NIST and ANL. ***