Molecular-thermodynamic prediction of critical micelle concentrations of commercial surfactants

Commercial surfactants have widespread use in many practical applications, including detergents, cosmetics, pharmaceuticals, enhanced oil recovery, an d surfactant-based separation processes. However, despite their practical r elevance, the solution behavior of commercial surfactants is not well under stood at a fundamental molecular level. With this in mind a new computation al approach, based on a recently developed molecular-thermodynamic theory o f mixed micellization, was developed to predict the critical micelle concen trations of commercial surfactants containing any number of surfactant comp onents. The new computational approach was then implemented, in the context of two user-friendly computer programs, PREDICT and MIX2, to molecularly p redict the critical micelle concentrations of several commercial surfactant s of known chemical composition, including their binary mixtures. The comme rcial surfactants examined include the cationic BTC-8358, the nonionics GEN APOL UD-079, GENAPOL UD-110, GENAPOL 26-L-98, and GENAPOL 26-L-50, and the anionic STEOL CS-330. The accuracy of the predicted critical micelle concen trations was found to be comparable to that attained in the case of single (pure) surfactants and their binary mixtures, thus demonstrating the practi cal utility of the computer-assisted molecular-thermodynamic modeling as a predictive tool in commercial surfactant characterization.