Shampoos Breakdown Oils
The detergents in shampoo are able to breakdown oils that accumulate on hair into tiny droplets. Once broken down, water is able to rinse the oil, as well as dust, flakes of skin and dirt out of the hair and down the drain. The detergents used in shampoos are able to access and clean tiny crevices found in hair, the hair shaft, and scalp because they can reduce the surface tension of the water. The synthetic detergents used in shampoos are actually soap free and therefore, do not react with the dissolved minerals that are found in hard water such as calcium and magnesium the way that soap does. Therefore, shampoos do not cause soap scum to build up on hair, even when used with hard water. Soap scum can make hair difficult to comb, dull looking, and it can be difficult to remove.
The chemical behavior of different detergents in water is used to classify the detergents as anionic, cationic, nonionic, or amphoteric. Shampoo is usually anionic, amphoteric, or a combination of both types because these are surfactant or surface acting agents. These agents help the surface area to become fully wet which assist in the cleaning process. Surfactants also keep dirt, oil, and other impurities suspended above the surface area and dispersed in the water. Therefore, they do not return to the surface from which they were just removed.
Normal, Dry or Oily
The strength of the shampoo, or its degreasing action, determines how much oil it will remove from the hair during washing. This is why it is important to choose the correct formulation for your hair type. A certain amount of natural oil needs to remain in the hair to retain shine, bounce, manageability and elasticity. Too strong of a shampoo may strip hair of tints, dyes, and natural oils, which are undesirable effects. Shampoos and conditioners can coat damaged hair, including split ends, making the hair look and feel healthier.