Surfactant refers to a substance that can significantly change the interface state of the solution system by adding a small amount. It has fixed hydrophilic and lipophilic groups, which can be aligned on the surface of the solution.
Surfactants are classified according to the dissociation properties of polar groups:
Anionic surfactants: stearic acid, sodium dodecylbenzene sulfonate;
Cationic surfactants: quaternary ammonium compounds;
Zwitterionic surfactants: lecithin, aminoacid-based, betaine-based;
Nonionic surfactants: alkyl glucoside, fatty acid glyceride, fatty acid sorbitan, polysorbate.
Surfactants have a series of physical and chemical functions such as wetting or anti-sticking, emulsification or demulsification, foaming or defoaming, solubilization, dispersion, washing, corrosion protection, and antistatic function. Natural surfactants include phospholipids, choline, and proteins, but more are artificially synthesized, such as sodium octadecyl sulfate C18H37SO4Na and sodium stearate C17H35COONa. Surfactants (cationic, anionic, non-ionic and amphoteric) provide multiple functions for specific applications, including foaming effect, surface modification, cleaning, emulsion, rheology, environmental and health protection. So there are many uses of surfactant.
Surfactants in detergents can help the cleaning agents effectively remove dirt when it is mixed with water. Without surfactants, soap cannot be mixed with water, but separated directly from water, making the cleaning process more difficult.
Surfactants can also be used as components of lubricants. As in shaving cream, they allow razors to easily remove stubble and reduce irritation.
Surfactants added to car engine lubricating oil help prevent particles from sticking to engine parts, so the parts can move easily and keep the car running normally.