Conformation and Dynamics of Polyelectrolytes in Non-Aqueous Solutions

本课题研究了介电常数对聚电解质的膨胀、分子间相互作用和粘弹性能的影响。本文得到的主要结论如下：1.聚电解质在非水稀溶液中的膨胀和相互作用本文所用的聚电解质是不同分子量的聚苯乙烯磺酸钠（NaPSS），它是由窄分子量分布的聚苯乙烯按照Vink的方法磺化制备的。样品的磺化度接近100%。在外加盐（NaCl）存在下，对NaPSS样品在介电常数（ε =111）比水（ε =80.1）高的甲酰胺稀溶液中的光散射和粘度进行了测量。结果表明，甲酰胺溶液的回转半径和特性粘数均大于水溶液，但甲酰胺溶液的回转半径和特性粘数对分子量的依赖性大于水溶液。 ...更多信息 结果表明，两种情况下的第二维里系数基本相同，且前者的第二维里系数也大于后者. 2.聚电解质在非水溶液中的粘弹性通过振荡实验、蠕变实验和蠕变恢复实验，测定了NaPSS样品在无盐和有盐（NaCl）存在下的水溶液和非水溶液中的零剪切粘度η ^0和稳态柔量J_e。这里使用的非水溶剂是甲酰胺和乙二醇（ε =38），它们的介电常数分别高于和低于水。结果表明，在稀、半稀和浓三个浓度区，甲酰胺溶液中的eta^0和J_e与水溶液中的分子量和聚合物浓度的依赖性几乎相同;而乙二醇溶液中的eta^0和J_e与中性聚合物在良溶剂中的三个浓度区的依赖性几乎相同。少

In this research project the effects of dielectric constant on expansion, intermolecular interactions and viscoelastic properties of polyelectrolytes were studied. The main conclusions obtained here are the followings.1.Expansion and Interactions of Polyelectrolytes in Non-Aqueous Dilute SolutionsPolyelectrolytes used here were sodium poly (stirene sulfonate) s (NaPSS) with different molecular weights, prepared by sulfonation of polystirenes with narrow molecular weight distributions according to Vink's method. The degrees of sulfonation of the samples are nearly 100%.Measurments of light scattering and viscosity were carried out for the NaPSS samples in dilute solutions of formamide, of which the dielectric constant (epsilon=111) is higher than water (epsilon=80.1), in the presence of added salt (NaCl). It was found that the radius of gyration and intrinsic viscosity in formamide solutions are larger than in aqueous solutions, though their molecular weight dependencies in the former a … More re similar to those in the latter, and the second virial coefficients in the former are also larger than in the latter. This means that the magnitude of excluded volume effects in formamide solutions is larger than in aqueous solutions.2.Viscoelastic Properties of Polyelectrolytes in Non-Aqueous SolutionsZero-shear viscosity eta^0 and steady state compliance J_e of the NaPSS samples were measuerd in aqueous and non-aqueous solutions in the absence and presence of added salts (NaCl) by oscillatory, creep and creep recovery experiments. Non-aqueous solvents used here were formamide and ethylene glycohol (epsilon=38), of which the dielectric constants are higher and lower than that of water, respectively. It was found that eta^0 and J_e in formamide solutions have almost the same molecular weight and polymer concentration dependencies as in aqueous solutions in dilute, semidilute and concentrated regions, while in ethylene glycohol solutions they have almost the same dependencies as for neutral polymers in good solvents in the three concentration regions. Less