Micellization behavior of [C 16-12-C 16], 2Br − gemini surfactant in binary aqueous-solvent mixtures

Abstract

The micellization behavior of bis cationic gemini surfactant, N, N′-dihexadecyl- N, N, N′, N′-tetramethyl-1,12-dodecanediammonium dibromide [C 16H 33N +(CH 3) 2-(CH 2) 12-N +(CH 3) 2C 16H 33, 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 ( Δ G m ° ) , the surface pressure at cmc ( π cmc), and the Gibbs energy of adsorption ( Δ G ad ° ) of the gemini surfactant have also been determined. The cmc, α, A min increases where as ( Δ G 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.