Effect of solubilization of CO 2 on the critical micelle concentration of sodium alkyl sulfonates

Abstract

The critical micelle concentrations (CMC) of aqueous solutions of octyl, decyl, and dodecyl sodium sulfonate have been measured as a function of CO 2 pressure. A thermodynamic model which describes the observed decline in CMC and determines the mole fraction of CO 2 in the micelle is presented. This model is then tested against reported solubility data of other gases in sodium alkyl sulfate solutions and found to be in good agreement. On the basis of these results it appears that the concept of a micelle Laplace pressure is not necessary to explain solubilization in micelles.