Silicone oil has many special properties:
○ Good heat resistance
Since the main chain of polysiloxane molecules is composed of -Si-O-Si-bonds, it has a structure similar to that of inorganic polymers, and its bond energy is very high, so it has excellent heat resistance.
○ Good oxidation stability and weather resistance
○ Good electrical insulation

Silicone oil has good dielectric properties, and its electrical characteristics change little with the change of temperature and cycle number. The dielectric constant decreases with increasing temperature, but only slightly. The power factor of silicone oil is low and increases with temperature, but it does not change regularly with frequency. Volume resistivity decreases with increasing temperature.
○ Good hydrophobicity

Although the main chain of silicone oil is composed of polar bonds Si-O, the non-polar alkyl groups on the side chains are oriented outwards, which prevents water molecules from entering the interior and acts as a hydrophobic effect. The interfacial tension of silicone oil to water is about 42 dynes/cm. When it spreads on the glass, due to the water repellency of silicone oil, it forms a contact angle of about 103oC, which is comparable to paraffin wax.
○ Small viscosity-temperature coefficient

The viscosity of silicone oil is low and changes little with temperature, which is related to the helical structure of silicone oil molecules. Silicone oil is a type of oil with the best viscosity-temperature characteristics among various liquid lubricants. This characteristic of silicone oil is very meaningful for damping equipment.
○ High compression resistance
Due to the helical structure of silicone oil molecules and the large distance between molecules, it has high compression resistance. Utilizing this characteristic of silicone oil, it can be used as a liquid spring, and compared with a mechanical spring, the volume can be greatly reduced.