Thermodynamics of Micellization of Cholic Acid Based Facial Amphiphiles Carrying Three Permanent Ionic Head Groups

This paper describes a series of cholic acid based facial amphiphiles carrying three ionic headgroups. Their micellization behavior in water was studied as a function of spacer length and alkyl tail length: both were found to have a small influence on the critical micellization concentration (cmc). Isothermal titration calorimetry was used to gain information on the thermodynamics of micellization. These surfactants show rather normal temperature-dependent behavior: Gibbs energy of micellization is almost constant, cmc increases, and enthalpy of micellization decreases with temperature, and both entropy and enthalpy contribute to the micellization.