This proposal is about the development of sustainable detergency based formulations, based on the blending of biosurfactants with conventional surfactants, and is part of a CASE award funded by EPSRC and Unilever. The focus of the project is to improve our understanding of the interfacial properties of complex multi-component mixtures of biosurfactants and conventional surfactants, and how to relate those properties to optimal performance. We request NR beam time on INTER to explore the surface mixing of the ternary mixture of C12E8 / LAS / SLES, the basis of the composition of most modern home and personal care products, and to which biosurfactants will be blended. In particular we wish to investigate the role of electrolyte in controlling the transition from highly non-ideal to ideal mixing, in this ternary mixture.