MICROEMULSIONS FORMED BY ALKYL POLYGLUCOSIDES AND AN ALKYL GLYCEROL ETHER

A surfactant is described which has the capability of mixing large amounts of hydrocarbon and water into a homogeneous solution. The surfactant system is a mixture of dodecyl polyglucosides with an average number of glucose units of 1.8 and a branched alkyl glycerol monoether which acts as a cosurfactant. A one-phase, liquid solution containing 4 wt % of this mixture, water, and a hydrocarbon (cyclohexane) can be prepared at any ratio of water to hydrocarbon (i.e., from neat water to neat hydrocarbon). This is achieved by varying the surfactant to cosurfactant molar ratio. Investigations by the NMR self-diffusion technique of the microemulsion microstructure give evidence for dramatic changes in the ratio of water-to-oil self-diffusion (by approximately 5 orders of magnitude). The microemulsion is of the oil droplets in water type at high surfactant to cosurfactant molar ratios and of the water droplets in oil type at lower ratios. At intermediate surfactant to cosurfactant ratios, the HLB of the surfactant mixture is balanced and a bicontinuous microemulsion with a low mean curvature surfactant layer is formed. At intermediate oil to water ratios, the microemulsion microstructure changes dramatically with small changes of the surfactant to cosurfactant ratio.