Synergistic Interactions in the Mixed Micelles of Cationic Amphiphile with Biopolymeric Glucoside Surfactants

The nature of micellar interaction and the interfacial behavior of the mixtures of the nonionic dodecyl, tetradecyl, hexadecyl polyglucoside surfactants with cationic dodecyl trimethyl ammonium chloride were studied by tensiometric observations. Various physicochemical properties such as surface activity parameters (CMC, gamma CMC, A(min)), the micellar and interfacial composition (X-m, X-sigma), interaction parameters (beta(m), beta(sigma)), and activity coefficients f(1)(m); f(2)(m); f(1)(sigma); f(2)(sigma)) were evaluated. The micellar mole fractions were always higher than ideal values, indicating high contributions of cationics in mixed micelles. Activity coefficients were less than unity, indicating synergism in micelles. The negative free energies of mixing showed the stability of the mixed micelles of the surfactants. The data of wetting, foaming, and emulsion properties of mixed surfactant systems were also supporting the observation of the marked synergistic interactions between the micelles.