What does surfactant mean?
A surfactant is a substance that lowers the surface tension of a liquid, enabling it to spread across a surface and wet it more evenly. This property makes surfactants valuable in soaps, detergents, cosmetics, paints, pharmaceuticals, and agricultural products. Many surfactants also help mix substances that would otherwise separate, which explains their frequent use as emulsifiers. In medicine, “surfactant” commonly refers to the natural lipid material produced in the lungs. It reduces the tendency of the tiny air sacs to collapse during breathing, especially in premature infants whose own supply is not yet fully developed. The term is predominantly scientific, but it is also widely used in consumer-product descriptions. Although ordinary language often substitutes soap or detergent, these words are not exact equivalents: a detergent is a cleaning formulation, whereas a surfactant is the surface-acting component or substance that gives such formulations their distinctive wetting and dispersing behavior.
nounA substance that lowers the surface tension of a liquid, allowing it to spread over and wet a surface more easily. Surfactants are used in detergents, cosmetics, paints, pharmaceuticals, and other products, and naturally occurring surfactants occur in the lungs.
- A substance that reduces surface tension and improves the spreading and wetting of liquids.
- A naturally occurring lipid material that coats the air sacs of the lungs and helps prevent their collapse during breathing.
"The formulation uses a mild surfactant to help the lotion spread evenly across the skin."
"A synthetic surfactant was added to the coating so that the ink would adhere evenly to the paper."
"Premature infants can receive laboratory-made surfactant to support their breathing when their own lung surfactant is insufficient."
The standard plural is used when referring to several such substances or to different types of surfactant.
"Different surfactants can produce very different foaming and cleaning properties."
Surfactant molecules give soap its power to spread: without them, water beads up and cleans poorly.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does surfactant come from?
Surfactant was formed in scientific English by blending “surface” and “active” with the suffix “-ant.” It became established during the 20th century as a shortened form of “surface-active agent,” a description based on the ability of these substances to act at interfaces and reduce surface tension.
How surfactant is actually used
The word is chiefly formal and technical. In general discussion, people often use the broader terms soap or detergent, although not every detergent is itself a surfactant and many surfactants are used outside cleaning products.