Hydrophobicity Improvement of Polluted Silicone Rubber by Plasma Jet in High Humidity Environment

Atmospheric pressure plasma jet can improve the hydrophobicity of polluted silicone rubber in a short time, which is contrary to conventional studies. It offers great application potential in the power system to avoid flashover induced by the low surface hydrophobicity of composite insulators. It is necessary to study the influence of high humidity on the hydrophobicity improvement under plasma exposure for its application in hot and humid regions, e.g. southern China. In this paper, plasma is used to treat polluted silicone rubber to improve its hydrophobicity in a high humidity environment. The high temperature vulcanized silicone rubber is artificially polluted by the solid layer method. The relative humidity is set as 40%, 75%, and 100%. The atmospheric pressure plasma jet is applied to the polluted silicone rubber. Contact angles are measured to characterize the hydrophobicity property of silicone rubber. The results show that plasma can accelerate the hydrophobicity transfer of the silicone rubber covered by a wet pollution layer. The hydrophobicity transfer of treated samples is much faster than the untreated one and it increases with the increase of plasma exposure time. The high humidity environment decreases the hydrophobicity recovery of polluted silicone rubber after plasma treatment. While a longer-time plasma treatment accelerates it.