Crystalizing the interface – The first X-Ray structure of an oil/surfactant/brine transition layer

Liquid-liquid interfacial phenomena are central in a wide variety of scientific disciplines and encompass down-to-earth aspects such as mayonnaise production, more complex processes in cellular biology and determine what drives the flow below the surface of the earth in an oil reservoir. It is the actual molecular structure at the boundary between two immiscible liquids that determines the interfacial properties. The experimental determination of such a structure has previously been unsuccessful. We have designed an experiment to enable crystallization of the interface between brine and a surfactant/organic phase. A single-crystal structure reveals, for the first time, how the structure and orientation of surfactants impact macroscopic measures such as interfacial tension.