Droplet structure in phosphocholine microemulsions

The small-angle neutron scattering (SANS) measurements reported here, for Winsor II microemulsions containing water, phosphocholines (PC's), and cyclohexane, are shown to give a wealth of information about droplet and interfacial structure. The surfactant chains are either well defined di-C-18 cis or trans isomers or a mixture of alkyl groups in naturally occurring Epikuron 200. For each surfactant and concentration three different neutron contrasts (core-shell-drop) were studied, and these data were analyzed together in terms of a Schultz distribution of core-shell particles. Although this is a simple model, it works well, and for the cis and trans isomers, differences in surfactant film thicknesses and oil mixing into the film can be discerned.