Computational prediction of the critical micelle concentration (CMC) of surfactants using the non-Bornian solvation model

Abstract

The non-Bornian solvation model was used to predict the Gibbs energy change for the adsorption–desorption processes of ionic (14 anionic and 9 cationic) surfactants and 19 non-ionic surfactants at the interface between oil (O) (=nitrobenzene) and water (W). Except for 10 non-ionic surfactants (polyoxyethylenes) having semi-hydrophobic –OC₂H₄– groups, both ionic and non-ionic surfactants showed a clear energy minimum in their adsorption–desorption processes, providing reliable values of Gibbs energies, and , for the two adsorption processes from their respective bulk phases to the interface (I). It was then found that the critical micelle concentration (CMC) for surfactants (especially for the ionic ones) is linearly related to the two independent variables, i.e., and .