Dynamics, Microviscosity, and Length Scales in Aqueous Polymer Solutions

在这个由化学部实验物理化学计划资助的项目中，Castner将使用随时间变化的光学技术对聚合物和聚合物基复杂流体中的摩擦进行实验研究。在这些实验中，将测试一个简单的假设，将聚合物溶液的微粘度与单体的微粘度联系起来，并探索三嵌段共聚物中的相关行为。光外差探测的拉曼诱导克尔效应光谱将被用来测量微粘度。飞秒光谱技术的最新进展将有助于改进测量。这些三嵌段共聚凝胶体系的剪切粘度变化很大，这将使微粘度假说得到深刻的检验。第二组实验将探索热可逆亲水聚合物凝胶的动力学。这些实验的结果将有助于更好地理解聚合物水溶液，并对设计用于药物输送和其他应用的改进的聚合物凝胶具有重要意义。这项研究将与本科生哈维·马德学院的理论家罗伯特·凯夫合作进行。PI还在道格拉斯学院的一门科学研究入门课程中指导一年级的女学生。因此，罗格斯大学、道格拉斯学院和哈维穆德学院的本科生可以在这一前沿研究领域获得经验。

In this project funded by the Experimental Physical Chemistry Program of the Chemistry Division, Castner will investigate friction in polymer and polymer-based complex fluids experimentally using time-dependent optical techniques. In these experiments a simple hypothesis relating the microviscosity of a polymer solution to the microviscosity of the monomer will be tested, and related behavior in triblock co-polymers will be explored. Optical-heterodyne detected Raman-induced Kerr effect spectroscopy will be used to measure the microviscosities. Recent advances in femtosecond spectroscopic techniques will help improve the measurements. The widely variable shear viscosity of these triblock co-polymer gels system will allow incisive tests of the microviscosity hypothesis. A second set of experiments will explore dynamics in thermoreversible hydrophilic polymer gels.Results of these experiments will lead to better understanding of aqueous polymer solutions and are of relevance to the design of improved polymer gels for drug delivery and other applications. This research will be be conducted in collaboration with theorist Robert Cave of Harvey Mudd College, an undergraduate institution. The PI also mentors first-year women students from Douglass College in an Introduction to Scientific Research course. As a result, undergraduates from Rutgers University, Douglass College, and Harvey Mudd College can obtain experience in this forefront research area.