Motions and Conformational Properties of Macromolecules in Solution

研究将在一般领域进行， 高分子构象变化动力学 在溶液中。振荡流的实验研究 双折射（OFB），粘弹性（VE），振荡流 二向色性（OFD）和时间分辨弹性光散射， 受周期性时变流的解决方案是 贯彻 一些研究将利用现有仪器 适用于高粘度环境中的宽有效频率范围测量 还提供广泛的温度依赖性的溶剂 信息;新仪器提供中度到高度 频率VE数据将用于获得宽频率 在低粘度溶剂中的覆盖率。 额外OFB 用于低粘度下高频研究的仪器 将构造和表征溶剂。 详细 浓度效应的实验研究， OFB上的温度、分子量和整体链拓扑 和VE的性质将继续和比较各种 理论预测。 弹簧模型计算 聚合物对VE和OFB贡献的频率依赖性 性能（稀溶液）将继续定期梳理 具有随机放置的分支位点，具有不等臂的星形，以及 随机分支链，以评估链的潜力 动力学，特别是这些技术， 详细的分支表征更典型的工业 聚合物比我们以前的工作中已经建模。 研究 局部结构（侧基，立构规整度， 微观结构）和溶剂化环境的修改， 聚合物链的邻域将继续并扩展到 包括更广泛不同聚合物结构。

Research will be conducted in the general area of the dynamics of conformational change in polymer molecules in solution. Experimental studies of oscillatory flow birefringence (OFB), viscoelasticity (VE), oscillatory flow dichroism (OFD) and time resolved elastic light scattering from solutions subjected to periodically time varying flows are to be carried out. Some studies will utilize existing instrumentation for wide effective frequency range measurements in highly viscous solvents which also provide extensive temperature dependence information; new instrumentation providing moderate to high frequency VE data will be employed to obtain wide frequency coverage in low viscosity solvents. Additional OFB instrumentation for high frequency studies in low viscosity solvents will be constructed and characterized. Detailed experimental studies of the effects of concentration, temperature, molecular weight, and overall chain topology on OFB and VE properties will be continued and compared with various theoretical predictions. Bead-spring model calculations of the frequency dependence of the polymer contribution to VE and OFB properties (dilute solutions) will be continued for regular combs with randomly placed branch sites, stars with unequal arms, and randomly branched chains to assess the potential of chain dynamics in general, and these techniques in particular, for detailed branching characterization of more typical industrial polymers than have been modeled in our previous work. Studies of the role of local structure (side groups, tacticity, microstructure) and solvating environment modifications in the neighborhood of polymer chains will be continued and expanded to include more widely different polymer structures.