高分子电解质溶胶－凝胶相转移与溶剂效应

Solvent Effects on Sol-Gel Transition for Polyelectrolyte Solutions

以溶质、溶剂间的协同作用作为高分子电解质体系的凝胶化条件，以松软粒子结构（Ｂｌｏｂ）间的三维逾渗的凝胶化模型，将高分子电解质体系的凝胶化分为松软粒子的形成和逾渗过程。结合海藻酸溶液的Ｃｕ２＋、Ｃａ２＋、Ｍｎ２＋和Ｃｏ２＋离子添加体系的凝胶化，分析了高分子电解质溶胶－凝胶相转移的实质，得到了体系相对粘度的临界指数ｋ＝０．９０～１．１４，与逾渗模型的预测值相吻合，探讨了松软粒子的形成对相转移临界点ｆｃ的影响，明确了临界点附近相对粘度的幂次公式ηｒｅｌ∝（ｆｃ—ｆ）－ｋ）的适用范围。

The coorperation of solute and solvent is taken as gelation condition.The three dimensional percolation of blobs is taken as gelation model.Phase transition of polyelectrolyte solution is then considered as the process of the formation and the percolation of blobs.Together with the gelation of alginate solutions induced by different divalent cations(Cu2+,Ca2+,Mn2+,Co2+),the nature of sol-gel transition has been suggested.Critical exponent of relative viscosity near the gelation point was obtained to be in the range of 0.90～1.14,which is in good agreement with the values predicted by percolation based on various models.Effect of the formation of bolbs on the gel point is discussed.In addition that,the correct range of f in the power-law relation of relative viscosity near gelation point,ηrel∝fc -f)-k,has been defined.