Dimethicones are a series of silicone polymers that contain only M and D units and conform to the structure shown in Figure 1.
Historically, dimethicones are the most understood and commonly used silicone products on the personal care market. They are homopolymers that are insoluble in water and in mineral oil. Dimethicones are also referred to with less technically acceptable terms such as silicone fluids, silicone oils or simply silicones. Dimethicones are sold by viscosity, as seen in Table 1, and vary from low molecular weight, thin materials to thick, sticky products.
Simethicone is an oral anti-foaming agent used to reduce bloating, discomfort and pain caused by excess gas in the stomach or intestinal tract. It is a mixture of polydimethylsiloxane and silica gel, and its structure is shown in Figure 2. There is dimethicone in simethicone, but there is no silica in dimethicone.