溶剂效应与海藻酸钠溶液溶胶-凝胶相转移

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）间的三维修滤过程作为体系的凝胶化模型，从而将高分子电解质体系的凝胶化分为松软粒子的形成和渗滤过程．结合不同浓度海藻酸钠溶液的Ca2＋离子深加体系的凝胶化，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＝0．90～0．97和相转移的临界点fc与聚合物浓度间的幂次关系fc～c-0.65，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．

Solvent Effects on Sol-gel Transition of Sodium Alginate Solutions

The cooperation of solute and solvent is taker as the gelation condition. The three dimensional percolation of blobs is taken as the gelation model. Phase transition of polyelectrolyte solution is then considered as a process of the formation and the percolation of blobs. By the study of the gelation of different concentration of alginate solutions induced by calcium cation, the nature of sol-gel transition has been suggested. Critical exponent of relative viscosity near the gelation point was determined as κ=0.900.97, A power-law relation was confirmed between the gelation point fc and alginate concentration c. In addition, the correct range of application of the power-law relation of relative viscosity near gelation point, ηrel ∝（fc-f）-k, has also been defined.