Dynamic Behavior of Complex Solutions Containing Semiflexible Polymers

这项研究集中在杆状聚合物溶液的动力学方面。荧光漂白回收法将测量荧光标记的棒状聚合物的示踪剂自扩散系数，以验证已通过光散射方法获得的大量数据集，并测试现有的自扩散理论及其与相互扩散的关系。将用脉冲场梯度核磁共振技术测量此类溶液中的溶剂迁移率，以解释随着聚合物浓度的增加，溶剂提供的阻力增加的原因。这将使我们能够与Doi和Edwards十年前的理论预测以及更新的发展进行比较。刚性不对称探针在刚性较弱的聚合物溶液中的扩散将被测量。最后，计划对具有长而灵活的侧链的杆件--“毛茸茸的杆件”--的行为进行研究。这些实验将开启对熔融态棒材分子动力学的研究，这与热致液晶的加工有关。

This research focuses on dynamical aspects of rod-bearing polymer solutions. Tracer self-diffusivities of fluorescently tagged rodlike polymers will be measured by fluorescence photobleaching recovery to verify the large data set already obtained via light-scattering methods, and to test existing theories of self diffusion and its relationship to mutual diffusion. Solvent mobility in such solutions will be measured by pulsed-field-gradient nuclear magnetic resonance techniques, in order to account for the increasing resistance offered by solvent as polymer concentration is increased. This will, enable a comparison with theoretical predictions made by Doi and Edwards a decade ago, as well as more recent developments. The diffusion of rigid asymmetric probes through solutions of less stiff polymers will be measured. Finally, an initiative into the behavior of rods with long, flexible sidechains-"furry rods"-is planned. These experiments will open research into the molecular dynamics of rods in the molten state, which relates to the processing of thermotropic liquid crystals.