This article is about mixtures of liquids. For the light-sensitive mixture used in photography, see Photographic emulsion. Two immiscible liquids, not yet emulsified An emulsion of Phase II dispersed in Phase I The unstable emulsion progressively separates The surfactant (outline around particles) positions itself on the interfaces between Phase II and Phase I, stabilizing the emulsion IUPAC definition Fluid system in which liquid droplets are dispersed in a liquid. Note 1: The definition is based on the definition in ref. Note 2: The droplets may be amorphous, liquid-crystalline, or any mixture thereof. Note 3: The diameters of the droplets constituting the dispersed phase usually range from approximately 10 nm to 100 μm; i.e., the droplets may exceed the usual size limits for colloidal particles. Note 4: An emulsion is termed an oil/water (o/w) emulsion if the dispersed phase is an organic material and the continuous phase is water or an aqueous solution and is termed water/oil (w/o) if the dispersed phase is water or an aqueous solution and the continuous phase is an organic liquid (an "oil"). Note 5: A w/o emulsion is sometimes called an inverse emulsion. The term "inverse emulsion" is misleading, suggesting incorrectly that the emulsion has properties that are the opposite of those of an emulsion. Its use is, therefore, not recommended. An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable). Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, homogenized milk, mayonnaise, and some cutting fluids for metal working. Graphene and its modified forms are also a good example of recent unconventional surfactants helping in stabilizing emulsion systems.