Determination of Physicochemical Parameters of Sodium Dodecyl Sulfate in Aqueous Micellar Solutions Containing Short-Chain Alcohols

Herein, the concentration effect of ethanol (in the molality range 0-9.5 mol.kg(-1)), 1-propanol (in the molality range 0-7 mol-kg(-1)), and 2-propanol (in the molality range 0-13 mol.kg(-1)) on the micellization of sodium dodecyl sulfate (SDS) in aqueous solutions has been studied at 298 K. The aggregation properties of SDS in aqueous solutions were investigated earlier in the presence of these alcohols but in the alcohol concentration range used in this work the micellization parameters (i.e., the critical micellar concentration, CMC, the dissociation degree of micelles), and especially, the molar conductance of micelles and monomers, the alcohol partition between micelles and the intermicellar solution have not been reported in such detail as here. Moreover, the published CMC values are often considerably different. For the systems studied here, the Gibbs energy of alcohol solubilization in the micelles, foaming properties, and refractive indices were determined. The studies presented here provide information about stability of surfactant micelles in the presence of short-chain alcohols, and the results obtained may be useful for the surfactant applications in different fields especially when water-poor media are required.