Microemulsions are clear, thermodynamically stable, isotropic liquid mixtures of oil, water and surfactant, frequently in combination with a cosurfactant.
[2] Microemulsions have many commercially important uses: Much of the work done on these systems have been motivated by their possible use to mobilize petroleum trapped in porous sandstone for enhanced oil recovery.
Microemulsion polymerization is a complex heterogeneous process where transport of monomers, free radicals and other species (such as chain transfer agent, co-surfactant and inhibitors) between the aqueous and organic phases, takes place.
Polymerization rate is controlled by monomer partitioning between the phases, particle nucleation, and adsorption and desorption of radicals.
Particle stability is affected by the amount and type of surfactant and pH of dispersing medium.
Calculations of the interfacial tension of the microemulsion with a coexisting oil or aqueous phase are also often of special focus and may sometimes be used to guide their formulation.
Alternative names for these systems are often used, such as transparent emulsion, swollen micelle, micellar solution, and solubilized oil.
These points combine to form regions with boundaries between them, which represent the "phase behavior" of the system at constant temperature and pressure.
It is believed that the mechanism for removing acid build up in car engine oils involves low water phase volume, water-in-oil (w/o) microemulsions.