ABSTRACT
Emulsions are disperse systems in which two—or sometimes several—almost insoluble liquid phases are intimately mixed. Except for special cases such as microemulsions or high internal phase emulsions with a foam structure, the internal phase is contained in the external phase in the form of spherical droplets. Thus in the simplest case there is either an oil in water (o/w) or a water in oil (w/o) emulsion. However for cosmetic and technical applications, multiphase emulsions are also quite common; for example a water in oil emulsion can be dispersed in water to obtain a w/o/w emulsion.
