Abstract: Surfactant p-octyl polyethylene glycol phenyl ether (Triton X-100) or cetyltrimethylammonium bromide (CTAB) was mixed with n-hexane, n-hexanol, and water for preparing reverse microemulsion. The effects of H+ concentration in water phase, concentrations of surfactant and cosurfactant on the microemulsion conductivity were studied. The results demonstrated that increasing H+ concentration in water phase enhanced the conductivity of reverse microemulsion greatly. The conductivity of microemulsion could be increased by 1~2 orders of magnitude as the H+ concentration increased from 1 mol•L-1 to 10 mol•L-1. When the H+ concentration of water phase was 10 mol•L-1, the conductivity of microemulsion enhanced as the water volume increased. The conductivity of these microemulsion increased to about 3200 μS•cm-1 when the volume ratio of water to oil was 3:10. The conductivity of microemulsion was enhanced as the Triton X-100 concentration increased, while it decreased with the increase of the CTAB concentration. The conductivity of non-ionic microemulsion decreased with the increase of cosurfactant concentration, while the conductivity of ionic microemulsion showed a camel shape change with the cosurfactant concentration.

Key words: Reverse microemulsion, Conductivity, H+ concentration, Surfactant, Cosurfactant, Temperature