Optical Probe Studies of Polymer Dynamics

9985782 Phillies聚合物溶液动力学出现在各种各样的科学，技术和社会背景中，从完全基础的（例如聚合物输运作为多体物理学的难题）到完全实用的（例如，聚合物添加剂作为快餐连锁店奶昔的增稠剂）。 溶解聚合物的物理性质在广泛的工业和商业应用中至关重要。 在这项资助下，将进行聚合物溶液弛豫的实验研究。 主要的实验技术将是准弹性光散射从介观各向同性和光学各向异性探针粒子，允许测量的平移和旋转耦合在介观距离尺度上的解决方案。 比较柔性链和半柔性链解中的探针扩散，将检验现代半柔性链动力学模型的有效性。 研究的小探针在浓缩的聚合物溶液将与竞争模型的聚合物溶液进行比较。 实验和文献数据将被用来学习如何传输性能的聚合物溶液遵循大分子的性质。 暑期奖学金将鼓励本科生从事研究工作。拟议的工作具有潜在的科学重要性和更广泛的影响。 了解聚合物溶液动力学将结束一个突出的挑战，多体系统的理论。 这项工作的一个典型的社会影响出现在现代生物技术行业：了解浓缩聚合物溶液中的运输将允许在浓缩溶液中进行生物聚合物产品纯化，避免目前对稀释溶液和昂贵的再浓缩步骤的普遍需求。

9985782PhilliesPolymer solution dynamics arises in a wide variety of scientific, technical, and social contexts, from the totally fundamental (e.g. polymer transport as a puzzle for many-body physics) to the utterly practical (e.g., polymeric additives as thickeners for fast-food-chain milk shakes). Physical properties of dissolved polymers are critical in a vast range of industrial and commercial applications. Under this grant experimental studies of relaxations in polymer solutions will be conducted. The primary experimental technique will be quasielastic light scattering from mesoscopic isotropic and optically anisotropic probe particles, permitting measurement of translational and rotational couplings in solution on mesoscopic distance scales. Comparison of probe diffusion in solutions of flexible and semiflexible chains will test the validity of modern models of semiflexible chain dynamics. Study of small probes in concentrated polymer solutions will be compared with competing models of polymer solutions. Experimental and literature data will be employed to learn how transport properties of polymer solutions follow from macromolecular properties. Summer fellowships will encourage undergraduates to pursue careers in research.The proposed work has potential scientific importance and broader implications. Understanding polymer solution dynamics would end an outstanding challenge to the theory of many-body systems. An exemplary societal impact of the work arises in the modern biotechnical industry: understanding transport in concentrated polymer solutions will permit biopolymer product purification to be performed in concentrated solutions, avoiding the current general need for dilute solutions and expensive reconcentration steps.