Science, Tech, Math › Science What Is a Surfactant? Share Flipboard Email Print Surfactants are found in detergents and foaming agents. Jamie Grill / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated March 31, 2019 Surfactant is the word that combines the terms "surface active agent". Surfactants or tensides are chemical species that act as wetting agents to lower the surface tension of a liquid and allow for increased spreadability. This can be at a liquid-liquid interface or a liquid-gas interface. Surfactant Structure Surfactant molecules are usually organic compounds that contain hydrophobic groups or "tails" and hydrophilic groups or "heads." This allows the molecule to interact with both water (a polar molecule) and oils (which are nonpolar). A group of surfactant molecules forms a micelle. A micelle is a spherical structure. In a micelle, the hydrophobic or lipophilic tails face inward, while the hydrophilic heads face outward. Oils and fats can be contained within the micelle sphere. Surfactant Examples Sodium stearate is a good example of a surfactant. It is the most common surfactant in soap. Another common surfactant is 4-(5-dodecyl)benzenesulfonate. Other examples include docusate (dioctyl sodium sulfosuccinate), alkyl ether phosphates, benzalkaonium chloride (BAC), and perfluorooctanesulfonate (PFOS). Pulmonary surfactant provides a coating on the surface of the alveoli in the lungs. It acts to prevent fluid accumulation, keep airways dry, and maintain surface tension within the lungs to prevent collapse.