Micellar Properties and Related Thermodynamic Parameters of the 14-6-14, 2Br− Gemini Surfactant in Water + Organic Solvent Mixed Media

Micellar parameters such as critical micelle concentration (cmc), degree of counterion dissociation (α), and aggregation number ( N agg ) of the cationic gemini surfactant hexamethylene-1,6-bis(tetradecyldimethylammonium bromide) (14-6-14, 2Br − ) have been determined in aqueous binary mixtures of dioxane (DO), dimethylformamide (DMF), and ethylene glycol (EG) by employing conductivity and fluorescence methods. An increase in the cmc and α values and a decrease in the N agg were observed when volume fractions (ϕ) of the studied organic solvents were varied (0 to 0.80 for conductivity and 0 to 0.50 for fluorescence studies) at 303.15 K. The temperature dependence of the cmc values provided information about various thermodynamic parameters and its effect on the selected compositions (ϕ = 0, 0.10, 0.20, 0.30, and 0.50) of the mixed media on varying the nature of the medium. The Gibbs energy of micellization (Δ G 0 m ) increased with the increase in the ϕ of the studied organic solvents. It was also observed that the increase in the cmc with the rise in temperature was more in the media containing a higher ϕ of the organic solvents.