Polyoxometallates (POM) are well defined transition metal clusters with a range of interesting catalytic, magnetic and optical properties. To make efficient use of these materials they are usually supported on other materials to provide a high surface area open network, allowing access to the POMs. The prospect of using solution self-assembly to structure POMs directly or evenly dispersed within a silica matrix is therefore attractive, so we are studying the synthesis and organisation of POM-headed surfactants, with C12, C14 or C16 hydrocarbon tails. Preliminary conductivity and SAXS data suggest these micellize in dilute solutions but in X-ray scattering the electron-dense headgroup dominates the scattering. Here we propose to study the size and shape of POM-amphiphiles micelles alone and in mixtures with a nonionic surfactant using contrast variation to determine the structures.