GHz-THz Dynamics and the Glass Transition in Polymers

了解分子运动的基本原理对于理解聚合物从宏观到纳米尺度的许多性质至关重要。在聚合物动力学的各个方面中，GHz-THz频率范围内的动力学值得特别关注，因为其对于信息和通信技术以及光子学中的应用的重要性。在这个程序中，在一个广泛的温度范围内的聚合物系统的GHz-THz动力学，从深在固态到深在液态，进行了研究。采用了三种实验技术：光和中子散射以及介电弛豫谱。这种组合提供了详细的微观信息的快速动力学，并有助于了解其与宏观性能的聚合物。该计划将促进对聚合物材料的GHz-THz特性和纳米尺度上分子运动背后的微观机制的理解。它将为新的理论方法的发展创造坚实的实验基础。预期结果将对聚合物科学产生重大影响，并在更广泛的方面对复杂系统的动力学，材料科学和物理学，以及通过更好地理解生物聚合物动力学对生物物理学产生重大影响。该计划包括与美国和欧洲的一些团体进行广泛合作。% GHz-THz动力学的先进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某些生物技术的进展具有重大影响。该计划还通过研究生和本科生积极参与这项研究，发展研究生课程，对未来技术的专家教育产生重大影响。在所提出的方向的进展将影响材料科学，物理学和生物物理学的各个领域。拟议的计划促进了积极的国际合作，并与NIST和ANL的国家多用户设施合作。***

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. ***