Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may act as
detergents, wetting agents, emulsifiers, foaming agents, and dispersants. Surfactants are classified according to polar head group. A non-ionic surfactant has no charged groups in its head.
The head of an ionic surfactant carries a net positive, or negative charge. If the charge is negative, the surfactant is more specifically called anionic; if the charge is positive, it is called cationic.
If a surfactant contains a head with two oppositely charged groups, it is termed zwitterionic or amphoteric.
Surfactants play an important role as cleaning, wetting, dispersing, emulsifying, foaming and anti-foaming agents in many practical applications and products, including detergents,
fabric softeners, emulsions, soaps, paints, adhesives, inks, anti-fogs, ski waxes, snowboard wax, deinking of recycled papers, in flotation, washing and enzymatic processes, laxatives. Also
agrochemical formulations such as Herbicides (some), insecticides, biocides (sanitizers), and spermicides. Personal care products such as cosmetics, shampoos, shower gel, hair conditioners
(after shampoo), toothpastes. Surfactants are used in firefighting and pipelines (liquid drag reducing agents). Alkali surfactant polymers are used to mobilize oil in oil wells. Surfactants are
used as plasticizer in nanocellulose, ferrofluids, and leak detectors. Surfactants are used with quantum dots in order to manipulate growth. and assembly of the dots, reactions on their
surface, electrical properties, etc., it is important to understand how surfactants arrange on the surface of the quantum dots.
