Micellization behavior of [C16-12-C16], 2Br− gemini surfactant in binary aqueous-solvent mixtures

The micellization behavior of bis cationic gemini surfactant, N,N′-dihexadecyl-N,N,N′,N′-tetramethyl-1,12-dodecanediammonium dibromide [C16H33N+(CH3)2-(CH2)12-N+(CH3)2C16H33, 2Br−] has been studied in binary aqueous mixtures of dimethyl sulfoxide, methanol, 1,4-dioxane, glycerol and ethylene glycol by conductivity and surface tension measurements at 300 K. The critical micellar concentration, degree of micelle ionization (α), surface excess concentration (Гmax), minimum surface area per molecule of surfactant (Amin), Gibbs free energy of micellization (ΔGm°)(ΔGm°), the surface pressure at cmc (πcmc), and the Gibbs energy of adsorption (ΔGad°)(ΔGad°) of the gemini surfactant have also been determined. The cmc, α, Amin increases where as (ΔGm°)(ΔGm°), Гmax, and πcmc decreases with increasing volume percentage of the solvents in the solvent–water binary mixture. The interfacial properties of the gemini surfactant, solute–solute, solvent–solute interactions and the effectiveness of a surface-active molecule in binary solvent systems have been discussed.