Membrane potential studies on surfactant solutions

Abstract

A membrane potential technique has been used to determine the degree of dissociation of eight different surfactant micelles. For two compounds, n-dodecyltrimethylammonium bromide and n-dodecylpyridinium bromide, the measurements have been extended over a 50° temperature range and values of 2.0 and 1.9 kcal mole^–1 respectively have been obtained for the energy of desorption of counterions from the micelle surfaces. Estimates of the heat of micellization as a function of temperature are also reported for these two compounds.