Micellization Behavior and Thermodynamic Properties of Triton X-100/CTAB Mixtures in Ethylene Glycol and Water Solvent Mixtures

The micellization behavior of the nonionic surfactant Triton X-100 (TX100) and the cationic cetyltrimethylammonium bromide (CTAB) binary mixtures was investigated in ethylene glycol (EG) and water mixtures using a tensiometric technique. We show that synergistic effects exist for surface tension reduction and mixed micelle formation. When the molar fraction of CTAB in the mixture is about 0.3, the synergistic effect is at its optimum. The critical micelle concentration of the mixture increases as the content of EG in the mixed solvents increases. The established theories of Rubingh and Maeda were applied to determine the molar fraction of the different components, the interaction parameters and several thermodynamic properties of the micellar phase. We found that the micelle composition and the interaction parameters from Rubingh's model and Maeda's model were in agreement.