Description of Temperature Dependence of Critical Micelle Concentration

Abstract

A new equation has been derived on the basis of <TEX>${\delta}G^o$</TEX> = -RT lnK, linear behavior of the enthalpy of micellization with temperature, and the Gibbs-Helmholtz relation. It describes correctly the dependence of critical micelle concentration <TEX>$(X_{CMC})$</TEX> on temperature and has yielded excellent fitting results for various surfactant systems. The new equation results in the linear behavior of the entropy of micellization with temperature and accounts for the compensation phenomena observed for the micellization in aqueous solutions, along with the linear dependence of the enthalpy of micellization on temperature. These results imply that the new equation of <TEX>$X_{CMC}(T)$</TEX> accounts for the temperature dependence of CMC correctly.