Properties of Binary Surfactant System of Alkyl Polyglycosides and α-Sulphonated Fatty Acid Methyl Ester

Abstract

Abstract Surface tension, fluorescence, zeta potential, dynamic light scattering and viscosity measurements have been used to investigate the properties of binary surfactant system of alkyl polyglycosides (APG) and α-sulphonated fatty acid methyl ester (MES). Through surface tension measurements, critical micelle concentration (CMC) of the mixture for different mixing mole fractions is determined and the values are all lower than those of pure constituent surfactants. Ideal CMC, molecule interaction parameters β and B have been calculated, and all these parameters indicate nonideal behavior and attractive interactions between the surfactant molecules. The micelle aggregation numbers (Nagg ) and the zeta potential (ζ) values of the binary surfactant system fall between those of constituent surfactants. The hydrodynamic radius (Rh ) of mixed micelle first increases and then decreases with the addition of MES. All these results show that nonionic surfactants facilitate the formation of larger micelles. The viscosities (η) of the mixtures are all lower than those of the pure component surfactants and with the addition of sodium chloride, the viscosity of mixture first increases rapidly and then decreases.