An understanding of surfactant aggregation on clay surfaces is important for detergency processes such as cleaning and pollutant removal. Studies have shown that the adsorbed character of surfactants on mica is markedly different from that of silica. We wish to extend the knowledge of surfactant aggregation on to mica surface, as a closer analogue to naturally occurring clay surfaces. Cetyltrimethylammonium bromide (C16TAB) adsorbed to mica surfaces has been seen to evolve with time, changing from initially adsorbed micelles which slowly flatten to form bilayers as K+ on the mica surface ion exchanges. We aim to structurally characterise changes in C16TAB adsorbed species on a variety of ion exchanged mica substrates (Li-, K-, Cs- and Ba-micas) using neutron reflectivity to study the effect that the basal plane cations have on the adsorption process and its kinetics.