The structure of colloidal crystals (dispersions of particles that spontaneously order in a regular array) is known to be influenced by solid boundaries. However there are few studies that exploit the power of neutron reflection to probe these solid/liquid boundaries. A fundamental study of the structure of colloidal dispersions and how it is influenced by an interface is proposed. The experiments will use a combination of neutron reflection and off-specular scattering to measure the profile normal to the surface and probe lateral surface structure for model systems composed of charged polystyrene particles in water. To optimise signal for the studies and exploit the possibility to probe both near the surface and in the bulk, samples of both deuterated and hydrogenous latex have been prepared.