which contain hydrophobic
hydrocarbon group connected with one or several hydrophilic groups dissociate into a positively
charged cation and a negatively charged anion in an aqueous
solution. If the head is negatively charged to carry the surface active properties,
it is called anionic surfactant, whereas a positively
charged head is the carrier of the
surface active properties in cationic surfactants. Typically cationic surfactants are based
on the nitrogen atom carrying the cationic charge such as amine and quaternary
Cationic surfactant is
considered to be poor cleaners but it contributes to the
fabric softening, the disinfecting properties, and the
grease-water interfacial tension reducing. Cationic surfactants
include quaternary ammonium compounds, amines (primary,
secondary, tertiary, diamines, polyamines, amine salts),
imidazoline compounds, betaine compounds, and esterquats.
is the widely used type of
surface active agent for laundry detergents, liquid cleaners and shampoos due
to excellent cleaning properties particularly effective at oily
soil cleaning and oil/clay soil suspension. Anionic surfactants are deactivated in
many hard water. To prevent deactivation, builders should be dosed.
Anionic surfactant is used as a emulsifier in
cosmetics, tooth paste, cream, shampoo, and acrylic
binder. Common soap is an anionic surfactant.
Carboxylate, sulfate, sulfonate and phosphate are the polar groups in
anionic surfactants. Anionic
surfactants include alkyl benzene
fatty acid salts,
lauryl sulfate, alkyl sulfate salts, sodium lauryl ether sulfate, alpha-olefin sulfonates,
phosphate esters, sulphosuccinates, alkyl phenol ether
sulfates, and isethionates.