This paper describes kinetic studies of metal complexation in the presence of micelles and vesicles of different charge type. The results are interpreted in terms of the effects of the surfactant self-assembly systems on the extraction of metal ions from an aqueous medium. It is found, in the case of anionic micelles, that the extracting ligand is preferentially located close to the surface of the surfactant aggregate, where it is held by hydrophobic interactions. In this location, it is accessible to the metal ion and so is readily complexed; there is no apparent tendency for the ligand to hide inside the micelle. The same situation is found for vesicles that are negatively charged to a similar surface potential. In contrast, when positively charged surfactants are used to form micelles, the metal ion is strongly repelled from the like-charged surface into the aqueous medium. Motion across a vesicle bilayer is found to be slow; furthermore, in our systems it was difficult to maintain a pH gradient for th...