What is an emulsion? The definition

An emulsion is a finely divided mixture of two normally immiscible liquids without visible segregation. Examples of emulsions are numerous cosmetics, milk or mayonnaise.

Structure of the emulsion

There is a finely divided mixture of two liquids, such as oil and water, in an emulsion. One liquid (phase) forms small droplets, distributed in the other liquid. The phase that forms droplets is called the inner phase or disperse phase. The phase in which the droplets swim is called the outer phase or continuous phase. Emulsions belong to the disperse systems and differ from mixtures of miscible liquids, such as ethanol and water. Emulsions are usually cloudy, milky liquids.

A distinction is made between water and oil emulsions in water-in-oil emulsions (W / O emulsions) and oil-in-water emulsions (O / W emulsions). Another important component of emulsions is the emulsifier (surfactant), which facilitates the formation of droplets and counteracts segregation (phase separation).