Partition of the w/o area of Winsor IV phases

Abstract Within the realm of existence of quaternary water/ionic surfactant/alchol/hydrcarbon w/o Winsor IV phases (so-called inverted microemulsions), the electrical conductivity undergoes nonmonotonous variations as the composition varies. In the general case, it is possible to define two lines, Γ 1 from conductivity maxima and Γ 2 from conductivity minima. Γ1 1 and Γ 2 partition the w/o Wins IV realm into three adjacent subareas, PM, ME, and MC, that can be assigned compositions corresponding, respectively, as the water content increases, to premicellar hydrated surfactant aggregates, inverted swollen spherical miceles, and micelle clusters. A similar behavior is put into evidence for ternary Winsor IV phases made up of water and dodecane with the well-balanced ionic surfactant Aerosol OT as the surface active agent. In some cases, Γ 2 cannot be defined and, consequently, it is not possible to identify the MC subarea.