Abstract:

In this paper, highly dispersed water-in-oil （W/O） microemulsion with uniform drop size was prepared by using the composite surfactant Tween80-Span80 and by taking cyclohexane as the oil phase. Then, for the purpose of obtaining the maximum solved water, the influences of such factors as the surfactant composition, four alcohol cosurfacants, the temperature and the salinity on the microemulsion stability were investigated by means of visual inspection and conductivity measurement. The optimum conditions for preparing the microemulsion were finally obtained. Experimental results show that, when the mass fraction of Tween80 in the composite surfactant is 60% and the mass ratio of the consurfactant ethanol to the composite surfactant （Km） is 1.0, the best W/O microemulsion system as an ideal microreactor can be prepared, and that, with the increase in temperature, the stable region of the microemulsion in phase diagram decreases and the influence of salinity on the region becomes slight.

Key words: water-in-oil microemulsion, stability, quasi-ternary phase diagram