The aggregation behavior was investigated in mixtures of sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) (anionic-rich catanionic) solutions. The study was conducted in solutions of water–ethylene glycol (EG) by means of surface tension, conductometry, cyclic voltammetry, zeta potential measurements, transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The degree of counterion dissociation ( α ), critical micelle concentration, aggregation numbers, interfacial properties, interparticle interaction parameters, and morphology of aggregates were determined. Based on regular solution theory, the cosolvent effects between SDS and CTAB as surfactants were also analyzed for both mixed monolayers at mixed micelles ( β M ) and the air/liquid interface ( β σ ). It was shown that the formation of large aggregates occurred in the presence of an excess of anionic surfactant. A phase transition from cylindrical micelles to spherical micelles in the anionic-rich regime was observed with an increase in the EG volume fraction. The inter particle interactions were assessed in terms of cosolvent effects on the micellar surface charge density and the cylindrical-to-spherical morphology change. Zeta potential and size of the aggregates were determined using dynamic light scattering and confirmed the models suggested for the processes taking place in each system.

中文翻译：

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共溶剂对富阴离子区域阳离子混合物中大型纳米结构自发形成的影响

在十二烷基硫酸钠 (SDS) 和十六烷基三甲基溴化铵 (CTAB)（富含阴离子的阳离子）溶液的混合物中研究了聚集行为。该研究是在水-乙二醇 (EG) 溶液中通过表面张力、电导测定法、循环伏安法、zeta 电位测量、透射电子显微镜 (TEM) 和动态光散射 (DLS) 技术进行的。测定了反离子解离度 (α)、临界胶束浓度、聚集数、界面性质、粒子间相互作用参数和聚集体的形态。基于常规溶液理论，还分析了作为表面活性剂的 SDS 和 CTAB 之间的共溶剂效应，用于混合胶束 ( β M ) 和气/液界面 ( β σ ) 的混合单层。结果表明，在过量阴离子表面活性剂存在下会形成大聚集体。随着EG体积分数的增加，观察到在富含阴离子的情况下从圆柱形胶束到球形胶束的相变。根据共溶剂对胶束表面电荷密度和圆柱形到球形形态变化的影响来评估颗粒间相互作用。使用动态光散射确定聚集体的 Zeta 电位和大小，并确认为每个系统中发生的过程建议的模型。根据共溶剂对胶束表面电荷密度和圆柱形到球形形态变化的影响来评估颗粒间相互作用。使用动态光散射确定聚集体的 Zeta 电位和大小，并确认为每个系统中发生的过程建议的模型。根据共溶剂对胶束表面电荷密度和圆柱形到球形形态变化的影响来评估颗粒间相互作用。使用动态光散射确定聚集体的 Zeta 电位和大小，并确认为每个系统中发生的过程建议的模型。