Micelle Formation: Thermodynamic Aspects and Characterization

The most prominent feature of surfactants is their ability to self-associate and form discrete aggregates in aqueous dispersions. Among the various self-assembled structures that are produced (vesicles, membranes, liquid crystals, etc.), micelles represent the simplest class of association colloids, and are widely used as nano-architectures for different applications. In spite of the vast literature, a complete understanding of all the experimental evidences related to the micellization process is still a work in progress. In particular, the thermodynamics and kinetics of micellization provide the crucial concepts for the control of dissociation and reconstruction of micelles, such as in the solubilization, stabilization and delivery of active ingredients, and in cosmetics, detergents, food technologym and in pharmaceutical formulations. In this contreibution, we offer an overview of the various structures formed by self-assembling amphiphilic molecules in water. The basic thermodynamics involved in self-assembly is described, and an overview of the experimental techniques used in the characterization of the structure and properties of these nanostructures is given.