Generally,a microemulsion consists of oil,water,surfactant and sometimes cosurfactant.Herein,we report a novel surfactantfree microemulsion(denoted as SFME)composed of benzene,water and ethanol without the amphiphilic molecular structure of traditional surfactant.The phase behavior of the ternary system was investigated,finding that there were a single-phase region and a two-phase region in ternary phase diagram.The electrical conductivity measurement was employed to investigate the microregion of the single-phase region,and a bicontinuous microregion and a benzene-in-water(O/W)microemulsion microregion were identified,which was confirmed by freeze-fracture transmission electron microscopy(FF-TEM)observations.The sizes of the microemulsion droplets are in the range of 20-50 nm.