Dynamic Viscoelasticity of Polymer Solutions

聚合物溶液的动态存储和损耗模量将使用一个非常敏感的谐振器仪器进行测量，该仪器已在首席研究员的实验室建造。对于稀聚合物溶液，本征模量可通过测量模量的浓度外推得到；这些模量反映了聚合物链的分子弛豫过程。将在稀溶液中研究具有匹配分子量的线性、星形和环状无规线圈聚合物；溶剂中的聚合物具有不同的热力学质量或特定的溶剂-聚合物相互作用；具有改变其分子柔韧性的侧链的聚合物；嵌段共聚物，其中嵌段可优先溶剂化；聚合电解质;以及结构构象发生可逆转变的聚合物。此外，还将对低浓度初始链相互作用引起的链弛豫的修饰进行系统的研究，此时链刚刚开始重叠。对于所有特性良好的聚合物将被使用，因此结果将适用于测试理论预测和与补充实验的比较。

The dynamic storage and loss moduli of polymer solutions will be measured using an extremely sensitive resonator instrument which has been constructed in the principal investigator's laboratory. For dilute polymer solutions, the intrinsic moduli will be obtained by concentration extrapolation of measured moduli; these moduli reflect the molecular relaxation processes of the polymer chain. Linear, star, and cyclic random- coil polymers of matched molecular weights will be studied in dilute solutions; polymers in solvents with varying thermodynamic quality or specific solvent-polymer interactions; polymer with side chains which modify their molecular flexibility; block copolymers where the blocks can be preferentially solvated; polyelectrolytes; and polymers which undergo reversible transformations of structural conformation. In addition, a systematic study will be undertaken with respect to modification of chain relaxations caused by initial chain interactions at low concentrations where chains just begin to overlap. For all well- characterized polymers will be used so that the results will be suitable for testing theoretical predications and for comparisons to complementary experiments.