Journal of Physical Chemistry, Vol.100, No.2, 701-708, 1996
Micellar Properties of Cationic Surfactants in Pure and Mixed States
The solution properties of the surfactants dodecyl-, tetradecyl-, and hexadecyl(cetyl)trimethylammonium bromide (DTAB, TTAB, and CTAB, respectively) as well as hexadecylpyridinium chloride (CPC) in pure and mixed states (binary and ternary combinations) have been studied. The critical micelle concentration (cmc), counterion binding, aggregation number, polarity, thermodynamics of micellization, interfacial adsorption, etc., have been quantitatively estimated by surface tension, conductance, spectrophotometry, fluorescence, and calorimetric methods. The micellar compositions, activities of the components in the micelle, and their mutual interactions have been estimated from Rubingh’s theory. The surfactant mixtures have been found to be nonideal, with a lower degree of counterion association compared to pure states, but possess more or less comparable micellar polarity and energetic parameters.
Keywords:SODIUM DODECYL-SULFATE;SOLUTION-AIR INTERFACE;AQUEOUS-SOLUTION;BINARY-MIXTURES;ACTIVE AGENTS;SOLUBILIZATION;MICELLIZATION;BROMIDE;TENSION;THERMODYNAMICS