As a side-effect, the curing process is also much slower in this case. In this case, the polymerization produces acetic acid, which is less chemically aggressive than HCl. For medical and domestic applications, a process was developed in which the chlorine atoms in the silane precursor were replaced with acetate groups. The polymerization reaction evolves hydrochloric acid. N Si(CH 3) 2Cl 2 + ( n + 1) H 2O → HO nH + 2 n HCl Industrial synthesis can begin from dimethyldichlorosilane and water by the following net reaction: The chemical formula of PDMS is CH 3 nSi(CH 3) 3, where n is the number of repeating monomer units. Its applications range from contact lenses and medical devices to elastomers it is also present in shampoos (as it makes hair shiny and slippery), food ( antifoaming agent), caulk, lubricants and heat-resistant tiles. It is one of several types of silicone oil ( polymerized siloxane). PDMS is optically clear and, in general, inert, non-toxic, and non-flammable. It is particularly known for its unusual rheological (or flow) properties. Polydimethylsiloxane ( PDMS), also known as dimethylpolysiloxane or dimethicone, is a silicone polymer with a wide variety of uses, from cosmetics to industrial lubrication.
