In detergent, a surfactant is the key ingredient responsible for cleaning. It’s a “surface active agent” with a dual nature: a water-loving (hydrophilic) head and a water-hating (hydrophobic) tail. The hydrophobic tail attaches to dirt and grease, while the hydrophilic head interacts with water, allowing the surfactant to form a micelle that traps the soil and pulls it away from the surface to be washed away in the solution.
The hydrophilic head of each surfactant is electrically charged. The charge can be negative, positive, or neutral. Depending on the charge of the hydrophilic head, the surfactant is classified as anionic, nonionic, cationic or amphoteric.