Micellar structure of gemini cationic surfactants: influence of the spacerlength

The enthalpies of micellisation of gemini and conventional cationic surfact ants have been determined using calorimetric measurements as a function of temperature. The differential molar enthalpies of micellisation depend on t he structure of the surfactants as well as on the temperature. As expected, a drastic increase of the enthalpies of micellisation are observed with an increase of the temperature. Moreover, calorimetric investigation of self- association process shows that the enthalpies of micellisation are much mor e exothermic for the gemini surfactants than for the conventional cationic surfactant. The higher values of the micellisation enthalpies are due to a higher micellar density of gemini surfactant micelles. (C) 2001 Elsevier Sc ience B.V. All rights reserved.