Study on hydrophobicity recovery characteristics and mechanism of HTV silicone rubber after corona deterioration

The hydrophobicity recovery characteristics of HTV silicone rubber (SIR) at different corona deterioration stage have been investigated with static contact angle method. The surface microstructure variation with the corona deterioration processing, along with the chemical composition change at the end of corona discharge have been analyzed by scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. Experiment results show that the hydrophobicity recovery characteristics vary with corona deterioration processing and the hydrophobicity recovery rate goes through four periods, which are "increase-reduction-increase-reduction". Moreover, after corona deterioration a certain time, the hydrophobicity can\´t recovery back to the initial value, even if the storage time is long enough. On the basis of surface appearance variation of HTV SIR, as well as the SEM, FTIR and XPS analysis results, the hydrophobicity recovery courses are explained in details and it is confirmed that the changes of surface microstructure and chemical composition act as important roles influencing the recovery speed and grade of hydrophobicity of HTV SIR.