Optical Probe Studies of Polymer Dynamics

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，从完全的基础(例如，聚合物传输作为多体物理的谜题)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是至关重要的。根据这笔赠款，将对聚合物溶液中的松弛进行实验研究。主要的实验技术将是介观各向同性和光学各向异性探针粒子的准弹性光散射，允许在介观距离尺度上测量溶液中的平移和旋转耦合。比较柔性链和半柔性链的解中的探针扩散，将检验现代半柔性链动力学模型的有效性。浓缩聚合物溶液中的小探针的研究将与竞争的聚合物溶液模型进行比较。实验和文献数据将被用来了解聚合物溶液的传输性质是如何由大分子性质决定的。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对多体系统理论的突出挑战。这项工作的一个典型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传输将允许在浓缩溶液中进行生物聚合物产品纯化，从而避免目前普遍需要的稀释溶液和昂贵的再浓缩步骤。

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.