Structure of Dense Sodium Di-2-Ethylsulfosuccinate/D2O/Decane Microemulsions

Small-angle neutron scattering is used to investigate the structure of single-phase AOT (sodium di-2-ethylsulfosuccinate)/${\mathrm{D}}_2$O/decane microemulsions containing equal volumes of water and oil and a variable concentration of surfactant. Each scattered-neutron spectrum exhibits a pronounced interaction peak. As the volume fraction of AOT is increased from 0.18 to 0.42, the peak position shifts to larger values of $Q$, and the peak height diminishes. The spectra are consistent with an ordered droplet phase, as opposed to a bicontinuous structure.