Recently there has been a vast expansion in understanding about the interactions between oppositely charged polyelectrolyte/surfactant mixtures. The use of neutron reflectometry has revealed not only the surface adsorption behaviour of a range of mixtures, but has also revealed important information about the nature of the interactions both at the surface and in solution and the relative stabilities of the different complexes present. It has been shown previously that it is possible to tune the strength of these interactions and hence the adsorption behaviour of mixtures by incorporating a nonionic surfactant into the mixture and varying the mixed surfactant composition. We now propose to explore the possibility of tuning the adsorption behaviour by studying mixtures containing SDS with two cationic polyelectrolytes which are known to exhibit different behaviour in the presence of SDS.