Microscopic Details of Polymer Dynamics: From Fast Dynamics to Segmental and Chain Relaxations

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TECHNICAL SUMMARY:Most of the unique properties of polymeric materials are defined by peculiarities of their molecular motions. Thus, understanding fundamentals of polymer dynamics is crucial for design of novel advanced materials with desired macroscopic properties. The proposed work is focused on various aspects of polymer dynamics, from microscopic behavior on picosecond time scales (fast dynamics) to the main structural relaxation (segmental dynamics) and chain dynamics. The main goal of this research is to unravel the microscopic mechanisms of the underlying phenomena and to explore role of chemical structure and inter-molecular interactions on molecular motions at different time and length scales. The proposed work aims at creation of a unified approach that will be able to describe polymer dynamics at different time and length scales and predict macroscopic properties of polymers based on their chemical structure. A broad number of experimental techniques (light, neutron and X-ray scattering, dielectric and mechanical relaxation spectroscopy) employed in this program provide detailed microscopic information on all components of polymer dynamics. The program includes broad collaborations with a few groups in the US (including industry) and in Europe. The results will have significant impact on polymer science, and in broader aspect on dynamics of complex systems, materials science and physics in general, and also on biophysics through a better understanding of dynamics of biological macromolecules.NON-TECHNICAL SUMMARY:The importance of polymer-based materials in our everyday life is growing dramatically and even broader perspectives are expected for the use of polymers in future technologies, including photonics, electronics and bio-technologies. Molecular motions present the key to many macroscopic properties of polymers. The proposed research focuses on fundamental understanding of molecular motions at different time and length scales and will impact various fields of materials science, physics and biophysics. Moreover, understanding the relationship between molecular structure and dynamics will have significant impact on design and synthesis of novel polymeric materials for advanced technologies. The proposed program involves broad international collaboration, collaboration with national multi-user facilities at NIST and ANL and with local industry. The proposed program also significantly impacts education of future specialists through active involvement of graduate and undergraduate students in this research, developments of graduate courses. Attention is also paid to work with underrepresented groups and K-12 students outreach.