Properties of Water/Propylene Glycol/Mixed Nonionic Surfactants/Mixed Oils Microemulsions

Water/propylene glycol/sucrose laurate/ethoxylated mono-di-glyceride/ isopropylmyristate/peppermint oil systems were formulated and characterized. The solubilization capacity of water in the oils is dependent on the surfactants molar ratio and temperature. The microemulsions were characterized by the volumetric parameters, density, excess volume, ultrasonic velocity and isentropic compressibility. The microemulsions densities increase with the aqueous phase content up to 80 wt%, then decrease. The excess volume decreases with aqueous phase content up to 80 wt%, then stabilizes. Ultrasonic velocities increase with the increase in the aqueous phase content and decrease with temperature. Analysis of the volumetric parameters enabled the characterization of structural transition along the microemulsion phase region. The particle hydrodynamic diameter of the oil-in-water microemulsions decreases with the increase in aqueous phase content and with the increase in temperature as determined by dynamic light scattering technique.