The surface structure of the AOT (sodium di-2-ethylsulfosuccinate) microemulsion system with equal volume fractions of ${\mathrm{D}}_2$O and decane, for AOT volume fractions of 0.42, 0.305, and 0.181, has been studied by a combination of x-ray specular reflectivity and scattering from the bulk. Scattering from the bulk material below the surface is consistent with Kotlarchyk’s interpretation of densely packed spherical micelles. Specular reflectivity from the surface implies a surface electron-density profile consistent with one to two layers of microemulsion droplets. The size of and distance between droplets is consistent with the respective values for the droplets in the bulk phase.

• Received 28 March 1988

DOI:https://doi.org/10.1103/PhysRevA.38.5817