We explain what a chemical emulsion is, what its phases are, how it is classified and what examples we find in everyday life.
An emulsion is a mixture of immiscible liquids.
What is an emulsion?
By chemical emulsion or simply emulsion is understood to be the more or less homogeneous union of two immiscible liquids, that is, they do not mix completely with each other. Emulsions consist of the dispersion of a liquid in another, both in different liquid phases.
They form what is ordinarily known as a colloid. Although these two terms are used interchangeably, emulsions differ from other colloids because they are always composed of liquid phases.
These two phases that make up an emulsion are always different and are classified as:
- Continuous phase. The phase that is predominant over the other, that is, that within which one of the liquids that make up the emulsion is dispersed. It is also called the "dispersing phase".
- Dispersed phase. The phase that is minority compared to the other, that is, that is dispersed within the dispersant phase.
Due to different chemical phenomena Y physical, emulsions always tend to color white, unless they are diluted emulsions (tending then to blue) or concentrated (tending to yellow). One and the other are distinguished from the concentration gradient of one phase in the other.
Many times an emulsion is formed due to the presence of substances emulsifiers, that is, particles that facilitate or promote the formation of emulsions between substances that would ordinarily find it much more difficult to do so.
Similarly, an emulsifier or emulsifier is a substance that stabilizes this type of mixtures preventing its phases from dispersing, acting as a binder material.
Emulsions can be of different types:
- Direct emulsions. Emulsions that combine a lipophilic dispersed phase (attracted by fats) and a continuous hydrophilic phase (attracted to the Water).
- Inverse emulsions. Emulsions that combine a hydrophilic dispersed phase and a lipophilic continuous phase, that is, the opposite of the direct ones.
- Multiple emulsions. Emulsions that have an inverse emulsion as the dispersed phase and an aqueous liquid as the continuous phase.
Examples of chemical emulsions
The egg is the emulsifier in mayonnaise.
Some common and everyday emulsions are: