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 how the Rhamnolipids R1 and R2 impact upon the highly non-ideal mixing in the C12E8 / LAS / SLES ternary mixture.