Influence of temperature on the hydrophobicity of silicone rubber surfaces [outdoor insulator applications]

The hydrophobicity status of silicone rubber (SIR) is affected by various factors. In order to study the influence of temperature on the hydrophobicity of silicone rubber, three kinds of SIR samples, which are clean surface, contaminated, and corona treated ones, were used. The static contact angle of a water droplet on the surface of the SIR was measured and was used in the evaluation of hydrophobicity. Based on the hydrophobicity, hydrophobicity transfer property and hydrophobicity recovery property, the influence of temperature on the hydrophobicity of silicone rubber was discussed. The experimental results showed that the hydrophobicity of the SIR material decreases with a decrease in temperature, with the transfer and recovery rate of hydrophobicity also decreasing, simultaneously. This paper considered that the change of surface free energy of SIR with temperature is a main reason for the presence of temperature-dependent hydrophobicity and the different hydrophobicity transfer properties are inherently related with the transfer speed of low molecule weight (LMW) components at different temperatures.