The UNIFAC group-contribution model is used to predict the critical micelle concentration (cmc) of nonionic surfactants in aqueous and nonaqueous solvents. For predicting the cmc, the phase-separation thermodynamic framework approach is used, where the micellar phase is approximated as a second liquid phase resulting from the liquid-liquid equilibrium between the solvent and the surfactant. The necessary activity coefficients are predicted by UNIFAC. The most promising UNIFAC model for this purpose was found to be the UNIFAC-Lyngby (Ind. Eng. Chem. Res. 1987, 26, 2274). To improve the results for surfactants containing oxyethylene chains, a new set of parameters was evaluated for this group, leading to still better cmc predictions for both water and organic solvents, as well as binary solvent systems.
- Vapor liquid equilibrium
- poly(ethylene glycols)
- activity- coefficients
Voutsas, E. C., Flores, M. V., Spiliotis, N., Bell, G., Halling, P. J., & Tassios, D. P. (2001). Prediction of critical micelle concentrations of nonionic surfactants in aqueous and nonaqueous solvents with UNIFAC. Industrial and Engineering Chemistry Research, 40(10), 2362-2366. https://doi.org/10.1021/ie0009841