Silicone, also known as dimethicone or cyclomethicone, is a derivative of silicon that is found in glass, quartz, and sand. Silicone has been an ingredient in cosmetics of the skin and hair since the 1950s. Silicones are inorganic polydimethylsiloxane polymers that are modified based on the product. The inorganic silicone molecule is flexible, with a long backbone of repeat units and different side chains that are linked to the silicone atom. The different side chain groups result in different types of silicone products. They have an oily, liquid consistency.
There are 2 types of silicone products: water-insoluble and water-soluble. The water-insoluble silicone products coat the hair and form deposits since they do not get washed out with water. While the hair remains frizz-free, it also slowly starts to form clumps and becomes brittle. Water-soluble silicone products (eg. dimethicone copolyol and PEG-modified dimethicone), however, are easier to wash away with water. All cosmetic products that contain chemicals ending in “-one” are indicative of containing silicone products.
Silicone Hair Treatment Procedure
Silicones coat hair strands, thus creating a smooth, shiny effect on the hair. Due to the high refractive index, the hair looks glossy. The hair looks healthy and remains detangled. The hair strands do not clump together and there is no resistance while combing. The hair ends are smooth and undamaged when coated with silicone. Silicone coating of hair provides protection from heat and also retains moisture in the hair. The heat transfer utilizes water as a conductor. By retaining moisture in the hair, silicones aid in the smooth transfer of heat to the hair fibre. This property is very important when the hair is subjected to styling techniques that use heat. Silicone-treated hair also retains the colour of hair that has undergone colour treatment.
The water-soluble silicones contain side chains that can be dissolved in water. Some of the examples are: PEG-dimethicone, hydroxypropyl polysiloxane, dimethicone copolyol, and lauryl methicone copolyol. Any silicone with the "PEG" prefix is water-soluble.
Some of the water-insoluble silicones are stearyl dimethicone, phenyl trimethicone, amodimethicon, stearoxy dimethicone, cyclomethicone, cetyl dimethicone, among others.
Silicone Hair Treatment Advantages and Disadvantages
As with any treatment, there are advantages and disadvantages to silicone treatment. Silicone is present in hair care products such as shampoos and conditioners.
Some of the advantages of silicone treatment are as follows:
• Smooth, shiny hair that looks healthy and has a reduced frizz - silicone coats the hair with a film providing a smooth texture to the hair.
• Hair is easier to comb and detangle
• Hair gains added volume
• Hair becomes soft in texture
• Silicones assist in the passage of nutrients into the shaft of the hair follicle.
• Moisture is sealed in with the silicone - hair is appropriately hydrated with silicone products.
While the positive aspects of silicone appear to be beneficial to hair, they also create a disadvantage in the long run. Silicones that coat the hair and retain the moisture are difficult to wash out. Water-soluble silicones can be washed away, yet there is a build-up of such silicones in the hair. While the hair is coated with silicone, no other product can access the roots of the hair, (eg, oil, water, protein nutrients).
Water-insoluble products can be washed away only with shampoos containing sulphates. The presence of water-insoluble silicones in the hair results in long-term damage to the hair. Long-term water-insoluble silicone deposits in the hair cause damage to the hair resulting in drying and breaking of hair. Straight or wavy hair tend to look greasy with the use of water-insoluble silicone hair products. Heavy silicone products also impart a lot of weight to the hair.
Silicone Hair Products
Silicone is found in hair products such as styling sprays, gels, shampoos, and conditioners.
• PEG-modified dimethicone