ABSTRACT
I. INTRODUCTION Surfactants (surface-active agents) are compounds whose molecules are fitted with pronounced lipophilic and hydrophilic moieties; they are amphiphilic molecules. A process whereby dissolved surfactant molecules react to the repelling action of surrounding water is aggregation to form various kinds of supramolecular structures. Largely depending on the molecular architecture of the amphiphile, a wealth of three-dimensional structures can be formed ranging from spherical and rodlike micelles to multilayer structures and to complex biological membranes, whose matrix is a lipid bilayer composed of phospholipids and glycolipids, incorporating proteins [1-3]. Most studies of micellar systems have been carried out on synthetic surfactants in which the polar or ionic headgroup may be cationic (e.g., an ammonium ion), anionic (e.g., a carboxylate, sulfate, or sulfonate ion), nonionic (e.g., hydroxy compound), or zwitterionic (e.g., an amine oxide or a carboxy-or sulfobetaine). Surfactants are often given trivial or trade names, and abbreviations based on either trivial or systematic names are freely used (Fig. 1).
