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 (Г_max), minimum surface area per molecule of surfactant (A_min), Gibbs free energy of micellization (ΔG_m°), the surface pressure at cmc (π_cmc), and the Gibbs energy of adsorption (ΔG_ad°) of the gemini surfactant have also been determined. The cmc, α, A_min increases where as (ΔG_m°), Г_max, and π_cmc 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.