Abstract: With n-hexanol as cosurfactant, quaternary ammonium Gemini surfactants C12-EOx-C12•2Br (x=1, 2, 3)formed reverse micelles in n-heptane. The critical reverse micelle concentrations (cmch) were determined using the absorption spectrum method with iodine as the probe. All values were less than the corresponding critical micelle concentration (cmcaq) in aqueous solution, where C12-EOx-C12•2Br formed the normal micelles. The cmch increased with increasing x, which was similar to the variation of cmcaq with x. The saturated amount of water solubilizated by the reverse micelles was enhanced by either increasing x or by raising the temperature.

Key words: Quaternary ammonium Gemini surfactants, n-hexanol/n-heptane solution, Reverse micelle, Solubilizing water