This proposal is part of a broad programme of collaborative research between RAL / Oxford and Unilever, using predominantly scattering techniques to investigate the nature of surfactant mixing at interfaces and in micelles. This proposal focuses on the mixed anionic surfactant sodium alkyl benzene sulfonate, LAS, with nonionic surfactants. We have previously shown that for LAS / C12EO8 (C12EO23) mixtures the surface adsorption undergoes a transition from a monolayer to a bilayer and eventually to a multilayer in the presence of CaCl2. This could have a significant impact upon many of the applications of mixed surfactants. We request here NR beam time on SURF to investigate further this novel surface behaviour. In particular we wish to investigate the role of different nonionic cosurfactants of different preferred curvatures and the impact of different LAS isomers.