Washing hair removes excess sweat and oil, as well as unwanted products from the hair and scalp. Often hair is washed as part of a shower or bathing with shampoo, a specialized surfactant. Shampoos work by applying water and shampoo to the hair. The shampoo breaks the surface tension of the water, allowing the hair to become soaked. This is known as the wetting action. The wetting action is caused by the head of the shampoo molecule attracting the water to the hair shaft. Conversely, the tail of the shampoo molecule is attracted to the grease, dirt, and oil on the hair shaft. The physical action of shampooing makes the grease and dirt become an emulsion that is then rinsed away with the water. This is known as the emulsifying action. Sulfate-free shampoos are less harmful to color-treated hair than normal shampoos that contain sulfates. Sulfates strip away natural oils as well as hair dye. Sulfates are also responsible for the foaming effect of shampoos. Shampoos have a pH of between Acidic shampoos are the most common type used and maintain or improve the condition of the hair as they don’t swell the hair shaft and don’t strip the natural oils.
Conditioners are often used after shampooing to smooth down the cuticle layer of the hair, which can become roughened during the physical process of shampooing. There are three main types of conditioners: anti-oxidant conditioners, which are mainly used in salons after chemical services and prevent creeping oxidation; internal conditioners, which enter into the cortex of the hair and help improve the hair’s internal condition (also known as treatments); and external conditioners, or everyday conditioners, which smooth down the cuticle layer, making the hair shiny, combable and smooth. Conditioners can also provide a physical layer of protection for the hair against physical and environmental damage.
Hair coloring
Hair coloring is the process of adding pigment to or removing pigment from the hair shaft. Hair coloring processes may be referred to as coloring or bleaching, depending on whether the pigment is being added or removed.
Temporary hair tints simply coat the shaft with pigments which later wash off.
Most permanent color changes require that the cuticle of the hair be opened so the color change can take place within the cuticle. This process, which uses chemicals to alter the structure of the hair, can damage the cuticle or internal structure of the hair, leaving it dry, weak, or prone to breakage. After the hair processing, the cuticle may not fully close, which results in coarse hair or an accelerated loss of pigment. Generally, the lighter the chosen color from one’s initial hair color, the more damaged it may be. Other options for applying color to hair besides chemical dyes include the use of such herbs as henna and indigo, or choosing ammonia-free solutions.
Perms and chemical straightening
Perms and relaxation using a relaxer or thermal reconditioning involve chemical alteration of the internal structure of the hair in order to affect its curliness or straightness. Hair that has been subjected to the use of a permanent is weaker due to the application of chemicals and should be treated gently and with greater care than hair that isn’t chemically altered.