Temperature dependence of the rate of micellization determined from ultrasonic relaxation data

Abstract

The temperature dependence of the rate of micellization of sodium octyl sulphate have been investigated in the range 288–333 K where the experimentally determined critical micelle concentration (c.m.c.) passes through a minimum. The rate constant associated with the step where a monomer dissociates from a micelle shows normal Arrhenius behaviour in this range, giving an activation energy of 29 kJ mol^–1. On the other hand the Arrhenius plot for the rate of association of a monomer to a micelle shows definite curvature. This result is discussed in terms of the minimum observed in the c.m.c. with temperature.