Dynamics of Associating Polymers: From Association to Segmental and Chain Relaxations

非技术总结：缔合聚合物是一类聚合物材料，从能源相关领域到生物医学技术的大量应用都是有希望的候选者。本研究的重点是对特殊设计的相互作用如何控制分子运动和缔合聚合物的宏观性质的基本理解。广泛的实验技术将用于分析不同时间和长度尺度上的分子运动，以及它们对单个聚合物分子的化学结构和刚性/柔韧性的依赖。对这类相对较新的材料的结构-性能关系的描述也将得到发展。这些知识对于合理设计和合成具有自我修复和刺激响应特性的新型“智能”材料对于许多未来的技术应用非常重要。它将对科学和工程的各个领域产生影响，包括材料科学、物理学、化学和生物物理学。该项目的一个重要部分是通过开发研究生课程和研究生和本科生积极参与研究来培养专家。还将注意与代表性不足的群体合作，并向K-12学生伸出援手。这项研究促进了与国际同事以及与橡树岭国家实验室的散裂中子源和纳米材料科学中心的合作。技术概述：通过可逆的非共价分子间相互作用形成的缔合聚合物，包括广泛的基础和技术上重要的材料。合理的设计、合成和制造新型缔合聚合物需要对局部可逆相互作用和主链柔韧性如何影响缔合聚合物的宏观性质有深刻的基本理解。尽管过去有大量的关注和努力，但缔合聚合物的链和结构动力学仍然知之甚少，特别是在熔融状态的情况下。在这个项目中，模型缔合聚合物的链和结构动力学将通过流变学、介电光谱、光散射和中子散射的结合来研究。新的实验方法和方案将通过借鉴传统聚合物、氢键玻璃形成液体和离子溶液领域的现有概念和技术来开发。此外，目前的理论模型的缔合聚合物将严格审查。本项目旨在为理解缔合聚合物的动力学建立现象学基础。

NON-TECHNICAL SUMMARY:Associating polymers are a class of polymeric materials that are promising candidates for a large number of applications ranging from energy-related fields to biomedical technologies. This research focuses on fundamental understanding of how the specially designed interactions control molecular motions and macroscopic properties of associating polymers. A broad range of experimental techniques will be employed to analyze molecular motions on different time and length scales, and their dependence on chemical structure and rigidity/flexibility of the individual polymer molecules. A description of structure-properties relationship in this relatively new class of materials will also be developed. This knowledge is important for rational design and synthesis of novel "smart" materials with self-healing and stimuli-responsive properties for many future technological applications. It will have an impact on various fields of science and engineering, including materials science, physics, chemistry and biophysics. A significant part of this project is the education of specialists through development of graduate courses and active involvement of graduate and undergraduate students in research. Attention will also be paid to working with underrepresented groups and to outreach to K-12 students. This research promotes collaborations with international colleagues and with the Spallation Neutron Source and Center for Nanophase Materials Sciences at the Oak Ridge National Laboratory. TECHNICAL SUMMARY:Associating polymers, formed by reversible non-covalent intermolecular interactions, include a wide spectrum of fundamentally and technologically important materials. Rational design, synthesis, and fabrication of novel associating polymers require a deep fundamental understanding of how the local reversible interactions and backbone flexibility affect the macroscopic properties of associating polymers. Despite intense attention and effort in the past, the chain and structural dynamics in associating polymers remain poorly understood, especially in the case of the melt state. In this project, the chain and structural dynamics in model associating polymers will be studied by a combination of rheology, dielectric spectroscopy, light scattering, and neutron scattering. New experimental methods and protocols will be developed by borrowing existing concepts and techniques from the fields of conventional polymers, hydrogen-bonded glass-forming liquids, and ionic solutions. In addition, the current theoretical models for associating polymers will be critically examined. This project aims to establish the phenomenological foundation for understanding the dynamics of associating polymers.