An Assessment of the Aggregation and Adsorption Behavior of the Sodium Dodecylsulfate–Cetyltrimethylammonium Bromide Mixed Surfactant System in Aqueous Medium

Sodium dodecylsulfate and cetyltrimethylammonium bromide mixtures are important catanionic systems, as they have an inherent tendency to form vesicle structures. Despite extensive studies on the phase behavior and microstructures, there is dearth of basic information on the aggregation and adsorption behavior of this mixed system. In this work the critical micelle concentration, surface tension reduction effectiveness, surface excess, mixed micelle and monolayer compositions, activity coefficients, interaction parameters, counterion binding and Gibbs energy terms of this mixed system are determined by measuring its surface tension and conductance as a function of composition. The dependence of mixed micelle composition on surfactant concentration has been successfully demonstrated.