Effect of plasma jet treatment on the receding contact angle of contaminated silicone rubber surface

Silicone rubber materials are widely used in the high-pressure field due to their excellent hydrophobicity and unique hydrophobicity transfer characteristics. The contact angle, as a macroscopic parameter characterizing the gas-liquid-solid interface characteristics, is one of the important standards for measuring the hydrophobicity of composite insulators. Previous studies have shown that the receding contact angle can better reflect the hydrophobicity of insulators than the advancing and static contact angle. Therefore, this article explores the effects of parameters such as voltage amplitude, power frequency, and processing time of plasma jet treatment on the receding contact angle of contaminated silicone rubber. The experimental results show that plasma jet treatment at a voltage of 6 kV can increase the receding contact angle of contaminated silicone rubber from 0° to about 60°, and within a certain range, the effect of receding contact angle improvement is better with the increase of treatment voltage, frequency, and time. Compared with plasma treatment to improve the static contact angle of contaminated silicone rubber, increasing the receding contact angle requires a longer migration time, taking more than 24 hours to achieve stability, and the recovery of the static contact angle is often within 1 hour.