Enthalpy–Entropy Compensation for Micellization and Other Hydrophobic Interactions in Aqueous Solutions

Abstract

The temperature dependence of the critical micelle concentration for 26 ionic and 48 non-ionic surfactants in aqueous solutions has been reexamined and used to calculate ΔH m 0 and ΔS m 0 , the heats and entropies of micellization, at 25 and 50 °C. ΔH m 0 and ΔS m 0 values exhibit a significant correlation with compensation temperatures (T c ) of 319 and 222 °K at 25 °C for the groups of ionic and non-ionic surfactants respectively. These results are compared with T c values which are expected to be characteristic of pairwise interactions between hydrophobic solutes.