The MES is representative of a promising group of anionic surfactants which have the potential for improved performance and biocompatibility / biosustainability, and their surface and self assembly properties have now been extensively studied. In most applications they will be used as mixtures with non-ionic or zwitterionic surfactants. Surface tension, light scattering and viscosity measurements indicate a strong synergy between MES and sulfobetaine surfactants, resulting in enhanced viscosity and changes in micelle structure, and the application of neutron scattering techniques is now essential in order to understand these potentially important phenomena. We request beam time on SANS2D to investigate the solution structure of MES / sulfobetaine mixtures in order to determine the variation in micelle composition and structure with solution concentration and composition.