Types of detergentsThe surfactant molecule is often described as tadpole-like because it has a fairly long fatty tail, which is water-insoluble or hydrophobic, and a small, often electrically charged head, which is water-soluble or hydrophilic. There are four possible combinations (Fig. 4.3):l. The anionic surface-active agents, in which the surfactant is an anion (i.e. it carries a negative charge) and the charge is concentrated in the hydrophilic or water-soluble head. These are the common actives in soaps, kitchen and laundry detergents.2. The cationic products (the opposite of anionic), in which the head carries a positive charge. These are used in the clothes dryer.