The surface tension of fluorosilicone oil is one of its core characteristics, which significantly affects its wettability (i.e. the ability of liquid to spread on the solid surface). Based on the relevant search results, the specific analysis is as follows:


I. Surface tension characteristics
‌Low surface tension range‌
The surface tension of fluorosilicone oil is usually ‌20–24 mN/m‌. This value is much lower than water (about 72 mN/m) and ordinary methyl silicone oil (about 21 mN/m), and even lower than polytetrafluoroethylene (PTFE).

‌Mechanism of action of molecular structure‌
Its low surface tension originates from the directional arrangement of fluorinated groups (especially trifluoropropyl -CF₃) in the molecular chain. Fluorine atoms have strong electronegativity, forming a tight hydrophobic and oleophobic molecular layer, which minimizes the surface energy. The surface tension of modified fluorosilicone oil (such as alkyl polyether modified type) can be further reduced to ‌<23 mN/m‌.

2. Wettability Performance
‌Significant hydrophobicity‌
Low surface tension directly causes fluorosilicone oil to show strong hydrophobicity and oleophobicity. Liquids are difficult to spread on its surface, and the contact angle increases, showing excellent anti-wetting and anti-adhesion properties.

‌Modification application in special scenarios‌
Through chemical modification (such as the introduction of polyether segments), water-soluble fluorosilicone oil can be prepared with a surface tension of about ‌23 mN/m‌, which has both wettability and antistatic functions. Fluorosilicone surfactants can also significantly reduce the surface tension of the system to be treated and improve wettability.

3. Application impact
‌Functional coating and lubrication‌
The formation of a molecular film containing -CF₃ groups on the surface of the substrate not only reduces the friction coefficient, but also gives the coating waterproof, anti-fouling and anti-scratch properties. For example, modified fluorosilicone oil can be used as a coating leveling agent to promote substrate wetting and prevent shrinkage.

‌Extreme Environment Stability‌
Within the temperature range of -60°C to 250°C, the low surface tension and hydrophobicity of fluorosilicone oil remain stable, making it suitable for harsh working conditions such as high temperature lubrication and vacuum sealing.