The Influence of Electrolytes on the Mixed Micellization of Equimolar (Monomeric and Dimeric) Surfactants

Abstract

The influence of halide ions of (sodium salt) electrolytes on the mixed micellization of a cationic gemini (dimeric) surfactant, hexanediyl-1,6-bis(dimethylcetylammonium) bromide (16-6-16) and a cationic conventional (monomeric) surfactant, cetyltrimethylammonium bromide (CTAB) have been investigated. The critical micelle concentration (CMC) of the mixed (16-6-16+CTAB) surfactants was measured by the surface tension measurements. The surface properties: viz., the surfactant concentration required to reduce the surface tension by 20 mN/m (C20), the surface pressure at the CMC (ΠCMC), the maximum surface excess concentration at the air/water interface (Γmax), the minimum area per surfactant molecule at the air/water interface (Amin), etc. of the mixed micellar surfactant systems were evaluated. In the absence and presence of electrolytes, the thermodynamic parameters of the mixed micellar surfactant systems were also evaluated.