Shampoos functional benefits

Synthetic surfactants are commonly used in shampoos, sometimes for reasons of cost and sometimes for performance. Non-ideal mixing in micelles can result when the repulsions between different surfactant head-groups are not uniform, such as when an anionic sulfonate is mixed with a non-ionic ethoxylate or when an anionic is mixed with a betaine. This causes the cmc of the mixture to be smaller than would be the case for ideal mixing, or for either surfactant alone. Such a reduction in cmc can be used to reduce the surfactant monomer concentration in a shampoo. This is an advantage since reducing the monomer concentration reduces the amount of eye and skin irritation experienced when the shampoo is used [904], Other synthetics offer other benefits. For example, some silicone surfactants can not only function as emulsifiers in hair and skin care products, but also act to improve feel, gloss, sheen, emolliency, conditioning and foam stabilization [905]. 

Other functional ingredients included in modern shampoos are those that confer benefits other than cleaning, such as agents to provide moisturizing body (e.g., proteins such as keratin, collagen, silk protein, hydro-... 

The main function of the primary surfactants in a shampoo is to provide a cleaning benefit. Primary surfactants are also necessary for adequate foam and viscosity control. As stated above, levels of surfactant between 8 and 20% are generally employed in shampoos. These levels are chosen primarily to provide acceptable lather and viscosity, since many common soils, e.g., sebum, are adequately cleaned at lower surfactant concentrations. 

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