Bola反离子诱导的高粘弹十六烷基硫酸钠蠕虫胶束溶液(英文)

Highly Viscoelastic Worm-Like Micelle Solution of Sodium Hexadecyl Sulfate Induced by Bolaform Counterions

利用稳态和频率扫描研究了十六烷基硫酸钠(SHS)与Bola盐(N,N'-双乙基二甲基-α,ω-乙烷溴化铵(Bola2Et)或N,N'-三甲基-α,ω-丁烷溴化铵(Bola4))混合体系的流变行为.实验结果表明两个体系均在45℃时形成了长蠕虫胶束,溶液呈现出高粘弹性,尤其是SHS/Bola2Et溶液表现出很高的弹性,零剪接粘度高达2520Pa's,表观上呈现胶状.这些结果归因于在Bola反离子诱导下,表面活性剂SHS与Bola反离子形成了静电吸引的2:1结构复合物.由于这两个Bola反离子的联接链长度均短于季铵离子的静电平衡距离,因此形成的复合物在形状上有利于蠕虫胶束生成.作为对比,添加简单的四甲基铵反离子无法诱导SHS形成蠕虫胶束,溶液仅呈现低粘度.

The rheological behaviors of mixed aqueous solutions of sodium hexadecyl sulfate（SHS）and a bolaform salt,either N,N＇-ethanediyl-α,ω-bis（ethyldimethylammonium bromide）（Bola2Et）or N,N＇-propanediyl-α,ω-bis（trimethylammonium bromide）（Bola4）,were investigated by steady-state and frequency-sweep measurements.The results showed that long worm-like micelles were formed in both systems at 45℃,and the solutions exhibited high viscoelasticities,especially the SHS/Bola2Et system in which the solution had very high elasticity.The zero-shear viscosity of SHS/Bola2Et was as high as 2520 Pa·s,and the system was gel-like.These results were attributed to the formation of 2：1 complexes by electrostatic attraction.Since the spacers of both Bola counterions were shorter than the distance between quaternary ammonium ions under electrostatic equilibrium,the generated complex in shape favored formation of worm-like micelles.In comparison,it was difficult to induce SHS to form worm-like micelles by the addition of tetramethylammonium counterions,and the solution exhibited low viscosity.