Microemulsions are clear, thermodynamically stable, isotropic liquid mixtures of oil, water and surfactant, frequently in combination with a cosurfactant. The aqueous phase may contain salt(s) and/or other ingredients, and the "oil" may actually be a complex mixture of different hydrocarbons and olefins. Microemulsion is a nanoparticle synthesis technique in which two immiscible fluids such as water in oil (w/o), oil in water (o/w) or water in supercritical carbon dioxide (w/sc CO2) are thermodynamically stabilized with the aid of a surfactant.