A surfactant is a compound that lowers the surface tension of a liquid, increasing the contact between the liquid and another substance. There are a wide variety of these compounds that work with oil, water, and an assortment of other liquids. Many companies manufacture a range of surfactants for various purposes, ranging from soaps to inks. They are also sometimes referred to as “wetting agents.”
The term is a compound of “surface acting agent,” referring to the fact that these substances interact with the surface of a liquid to change its properties. They work through a process known as “adsorption,” which means that they accrete on the surface of a liquid, creating a film that reduces its surface tension.
One of the most famous surfactants is soap, which is used to break the surface tension of water so that it can penetrate more fully. The foaming action of soap helps water get under dirt and grease on surfaces like dishes, hands, and fabrics, allowing the water to carry the dirt away. As anyone who has tried to wash without soap knows, the high surface tension of plain water makes cleaning very difficult.
Surfactants can also work as lubricants, as is the case with shaving a cream, which makes it easier to run a razor along the skin to remove unwanted hair. They are also used in sanitizing products, anti-fogging liquids, adhesives, emulsifiers, and fabric softeners, among numerous other substances. In some cases, these compounds may be toxic or pose a health risk, depending on the materials they contain, and it is a good idea for users to read labels to make sure that they are being used properly.
The term is also used in the medical community to refer specifically to a substance secreted by the cells that line the lungs. Pulmonary surfactant makes it easier for people to breathe by reducing surface tension in the lungs. Without this substance in the lungs, people would have trouble breathing, and their breathing would be much noisier. Many of the respiratory problems in premature infants are caused by lack of surfactant, and some rare lung diseases can also interfere with its production and function.