What Are Surfactants?

A surface-active agent, or surfactant, is a substance that reduces the surface tension of the liquid it’s dissolved into and spread evenly across a surface. It also helps to stir up and trap dirt, making it easier to remove from a surface. Surfactants can act as foaming or wetting agents, emulsifiers, detergents, cleaners, disinfectants, and more.
All surfactants have a hydrophilic head and a hydrophobic tail. This means that the head of the molecule is attracted to water, and the tail is repelled by water. When added to water, the head of the molecule is attracted to the water, and the tail essentially sticks up out of the water. This is what reduces the surface tension.
As the surfactant concentration increases, micelles or “balls” of surfactant form. This formation is crucial as it makes the breakdown of substances that are normally insoluble in water, such as oil, possible.
The water loving heads form the outer circle of the micelles and the tails are attached to the fat-soluble soils, forming a ball around these soils. The attraction between the tails and the soils helps loosen the soils from the surface and trap them in the micelles.
The soils, suspended in the micelles, are then easy to wash away.
Surfactants are an important part of cleaning chemicals as they trap dirt, oil, and other soils to lift them away from surfaces.