The most common type of silicone oil is the linear polyorganosiloxane compound, which is arranged in a spiral pattern and can slide easily among each other. Silicone oil exhibits excellent thermal stability and fluidity at extreme temperatures. Polydimethylsiloxane is the main organosiloxane polymer, but other organic groups (phenyl, vinyl, epoxide, or amino) can also be incorporated into the siloxane polymer, providing special properties or reactivity in certain cases. 
Silicone molecule structure
The repeating chains of silicone oil and other silicon oxide polymers consist of alternating silicon atoms and oxygen atoms. Silicone oil is composed of linear repeating chains of silicon and oxygen, where each silicon atom also has two carbon-based substituents, which are usually methyl groups. Silicone oil can have a certain degree of polymerization degree, in other words, the average number of repeating siloxane groups in the polymer chain varies from a few units to several thousand units. By replacing a small portion of the methyl groups with phenyl or amino functional groups, the way silicone oxide polymers interact with other materials can be changed. Adding active organic groups to silicone oxide polymers can also integrate silicone oxide polymers into various types of organic polymers, which can bring some unique properties compared to standard organic polymers. 
Properties of Silicone Oil
The viscosity of silicone oil varies greatly, ranging from 0.65 cs to 2,000,000 cs, and the viscosity remains constant over a wide temperature range. Compared to some organic polymers, silicone polymers also exhibit significant thermal stability (up to 250℃), which is due to the special chemical bonds between silicon and oxygen in the polymer chains. Due to the low surface tension of silicone, it can easily spread on the surface, thus having high compressibility compared to different hydrocarbons and mineral oils. Silicone oxygenane polymers have good dielectric properties, resistance to shear force, resistance to natural aging, oxidation resistance and hydrolysis resistance.