Cationic gemini surface active ingredient effect of organic solvents on miselization behavior

Surface active agents (surfactant) have a wide range of uses due to their molecular structure. Because these substances contain two opposite groups both the hydrophilic head group and the hydrophobic chain in the same molecule. Gemini surfactant molecules are substances in which two hydrophilic head groups and two hydrophobic chain groups are connected by the spacer chain in the same molecule. In this study, critical micelle concentration (CMC) values and ionization degrees (α) of the cationic gemini surfactant N,N'-(oxybis(ethane-2,1-diyl))bis(N,N-dimethyldodecane-1-ammonium) bromide (12-2-O-2-12) were found in pure water at temperatures of 25, 30, 35 and 40 °C. For these values, change graphs of specific conductivity values obtained for different concentrations of the surfactant were used. The same measurements and graphs were made for cationic gemini surfactant and solvent mixtures and KMK and α values were obtained for surfactant-solvent mixtures. Methanol, ethanol, isopropanol, dimethylformamide and dimethyl sulfoxide were used as solvents at the rates of 10% and 20% (v/v) by volume. Using the KMK and α values obtained for pure water and water-solvent mixtures, the thermodynamic properties of the mixtures were examined, including standard Gibbs free energy (∆Gom), Standard Gibbs free energy of transfer (∆Gom,trans), enthalpy (∆Hom) and entropy (∆Som) values for the micellization of the surfactant. It was observed that the critical micelle concentration and ionization degree values increased in the presence of solvent and with the increase in solvent volume percentage. In addition, with the addition of solvent, the Gibbs free energy values of micellization decreased and negative enthalpy values showed that the process was exothermic.