Physicochemical studies of the hexadecylpyridinium bromide micellar system in the presence of various concentrations of sodium bromide using a surfactant-selective electrode

Abstract

A membrane electrode selective to hexadecylammonium bromide has been used to study the micellization of the surfactant in the presence of varying amounts of sodium bromide at 27°C. It is found that there is an inverse relationship between the amount of NaBr added and the critical micelle concentration and the degree of counter-ion dissociation of the system studied. The aggregation number of the micelles formed has been determined and found to increase with the concentration of NaBr added. Some evidence for the formation of dimer forms of the surfactant prior to the micelle formation is found at higher concentrations of the electrolyte.