Effect of Ascorbic Acid on the Colloidal and Micellar Properties of Anionic, Cationic, and Nonionic Surfactants: Conductivity, Volumetric, Viscometric, and Fluorescence Study

The influence of ascorbic acid on the micellar, thermodynamic, and volumetric properties and viscometric and aggregation behavior of anionic surfactant sodium dodecylsulfate, cationic surfactant cetylpyridinium bromide, and nonionic surfactant hexadecylpoly[oxyethylene(20)] alcohol was studied. Micellar and surface thermodynamic data were obtained from the temperature dependence of critical micelle concentration. The apparent molar volumes, standard partial volumes, and standard transfer volumes for surfactant-ascorbic acid-water systems were calculated. On the basis of dependence of the relative viscosities on concentration, the viscosity B-coefficients of the Jones-Dole semiempirical equation were calculated for both premicellar and postmicellar regions. From the fluorescence-quenching measurements it was found that both the hydrodynamic radius and the micellar aggregation number decreased with the increase of ascorbic acid concentration. This study allowed us to conclude that ascorbic acid solubilized in micelles.