Tuesday, July 31, 2012
Monday, July 30, 2012
- One way to distribute the hair's natural oils through the hair is by brushing with a natural bristle brush. The natural bristles effectively move the oil from the scalp through to the hair's mid-lengths and ends, nourishing these parts of the hair. Brushing the scalp also stimulates the sebaceous gland, which in turn produces more sebum. When sebum and sweat combine on the scalp surface, they help to create the acid mantle, which is the skin's own protective layer.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 harming on 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 4 and 6 and do not contain soap. Soapless shampoos are acidic and therefore closer to the natural pH of hair. Acidic shampoos are the most common type used and maintain or improve the condition of the hair as they don't swell the hairshaft 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.