Critical micelle concentration and the transition point for micellar size distribution

Abstract

The equation assumed by Ben-Naim and Stillinger for the free energy of micellization is used to demonstrate that, contrary to their assertion, the critical concentration Ccrit corresponding to a transition in the shape of the micellar size distribution has a value close to the conventional cmc. The ratio cmc/Ccrit is shown to decrease sharply from the large value of 20 obtained by Ben-Naim and Stillinger, to a value of 1.55, if one of the parameters (σ) is assigned a physically more plausible value. This value accounts better for the cooperative self-association of the surfactant molecules. © 1981 American Chemical Society.