Dynamic Viscoelasticity of Polymer Solutions

聚合物溶液的动态存储和损耗模数将使用在首席研究人员实验室建造的极其灵敏的谐振器仪器来测量。对于稀溶液，内禀模数通过测量模数的浓度外推得到，这些模数反映了高分子链的分子弛豫过程。具有匹配分子量的线形、星形和环状无规卷曲聚合物将在稀溶液中进行研究；在具有不同热力学性质或特定溶剂-聚合物相互作用的溶剂中的聚合物；具有改变其分子柔韧性的侧链的聚合物；嵌段可优先溶剂化的嵌段共聚聚合物；聚电解质；以及经历结构构象可逆转变的聚合物。此外，还将进行一项系统的研究，以研究在低浓度下由链的初始相互作用引起的链松弛的修饰，其中链刚刚开始重叠。对于所有特性良好的聚合物，将使用这样的结果来检验理论预测，并与补充实验进行比较。

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.