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 (Π_CMC), the maximum surface excess concentration at the air/water interface (Γ_max), the minimum area per surfactant molecule at the air/water interface (A_min), 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.