ABSTRACT
Surfactants (also called amphiphiles and sometimes detergents, emulsifiers, and now more rarely soaps) are surface-active agents that contain both apolar residues, typically linear alkyl groups, and polar or ionic headgroups [1–6]. Some examples are shown in Scheme 1. In water or in solvents such as sulfuric acid [7], hydrazine, diols, or triols [8,9] that associate in three dimensions, surfactants and other components aggregate to form association colloids such as micelles, microemulsions, and vesicles, whose size and shape depend on the structures and concentrations of components present (Fig. 1) [1–6]. These association colloids are composed of oil-like and solvent-like regions separated by an interfacial region that is the locus of chemical reactivity in aggregated systems. Association is driven by the solvophobic effect, which reduces unfavorable interactions of apolar groups with solvent. The term “hydrophobic” applies strictly to aqueous media but is often used more generally. Most kinetic work with normal micelles, microemulsions, vesicles, and polyelectrolytes is based on aqueous media, and we focus attention on water as solvent [6,10–12].
