三聚阴离子表面活性剂/阳离子添加剂混合体系的流变行为

表面活性剂的分子结构对蠕虫胶束的形成与性质有着重要影响。本文以十四酸和间苯三酚为起始原料，合成了一种三聚阴离子表面活性剂（2, 2', 2"-（苯基-1, 3, 5-三（氧））-三-十四酸钠，简写为Ph-TrisC₁₄Na），并通过稳态和动态流变测试，研究了单组分的Ph-TrisC₁₄Na和Ph-TrisC₁₄Na/阳离子添加剂体系的粘弹性质。阳离子添加剂分别为正丁基三甲基溴化铵（C₄TAB），正己基三甲基溴化铵（C₆TAB）和正辛基三甲基溴化铵（C₈TAB）。结果表明，依赖于独特的分子构型，Ph-TrisC₁₄Na分子自身即可形成蠕虫胶束，使溶液表现出明显的粘弹性。阳离子添加剂的加入可进一步优化Ph-TrisC₁₄Na的分子几何结构，促进蠕虫胶束更为快速地生长。随着阳离子添加剂疏水链长的增加，溶液的粘弹性显著增强，体系微结构对添加剂的敏感性也增加。对于50 mmol·L^-1的Ph-TrisC₁₄Na溶液来说，在C₈TAB与Ph-TrisC₁₄Na的摩尔比为0.5时，体系的零剪切粘度可达1535 Pa·s，蠕虫胶束的长度则达到4.0-7.5 μm。该体系体现出低聚表面活性剂在构筑表面活性剂粘弹溶液方面的优势，可拓展高粘弹性阴离子蠕虫胶束体系的研究范围。

Rheological Behavior of Trimeric Anionic Surfactant/Cationic Additive Mixed Systems

Surfactant structure is known to have a significant effect on the formation and properties of wormlike micelles. In the present study, a new trimeric anionic surfactant (sodium 2, 2', 2"-(benzene-1, 3, 5-triyltris(oxy)) tritetradecanoate, abbreviated as Ph-TrisC₁₄Na) was synthesized from myristic acid and m-trihydroxybenzene. The viscoelastic properties of single component Ph-TrisC₁₄Na and Ph-TrisC₁₄Na/cationic additive systems were subsequently investigated by steady state and dynamic rheological measurements, using butyltrimethyl ammonium bromide (C₄TAB), hexyltrimethyl ammonium bromide (C₆TAB), and octyltrimethyl ammonium bromide (C₈TAB) as the additives. The results show that the unique molecular structure of Ph-TrisC₁₄Na enables the formation of wormlike micelles when this compound is the sole component of the solution, and generates solutions with significant viscoelasticity. The addition of cationic species further optimizes the molecular geometry of the Ph-TrisC₁₄Na and promotes the rapid growth of wormlike micelles. Additives with longer hydrophobic chains have a marked effect on the viscoelasticity and the microstructure of the mixed solution systems. A 50 mmol·L^-1 Ph-TrisC₁₄Na solution exhibits a zero shear viscosity of 1535 Pa·s together with micelle lengths in the range of 4.0 to 7.5 μm at a C₈TAB to Ph-TrisC₁₄Na molar ratio of 0.5. The present system shows the advantage of using an oligomeric surfactant in viscoelastic surfactant solutions. The information obtained from this work should be beneficial with regard to expanding the scope of highly viscoelastic anionic wormlike micellar systems.