Shampoo Formulation

The document from 2007 explains that the primary function of shampoos is to clean hair, primarily through the action of surfactants, with anionic surfactants being the most common type used for foaming and cleaning. These anionic surfactants can be sulfates, sulfonates, carboxylates, or phosphates. Amphoteric surfactants can change their net charge based on pH, and betaines can increase shampoo viscosity when used with anionic surfactants. Since hair has a net negative charge, conditioning can be achieved by adding positively charged fatty materials to the shampoo, which then attach to the hair. Shampoos also contain other additives like anti-dandruff agents, humectants, and preservatives to provide additional benefits.