Carboxylates Surfactants are compounds that lower the surface tension between two liquids, between a gas and a liquid, or between a liquid and a solid. They may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants. Beyond soaps and detergents, surfactants are used in lubricants, inks, anti-fogging liquids, herbicides, adhesives, emulsifiers and fabric softeners.