Effect of contamination particle size on surface charge dissipation rate of plasma-treated silicone rubber

The study of plasma penetration in porous materials is very important for its application. In this paper, contaminated silicone rubber is used as the experimental samples while the surface kaolin layer on it is used to simulate the porous inorganic layer. The process of plasma treatment on the contaminated silicone rubber is decomposed into the process of plasma penetrating the porous inorganic layer on the surface and the interaction between the penetrated high-energy particles with the surface of silicone rubber. In the light of the fact that the surface charge dissipation characteristics are very sensitive to plasma treatment, the surface charge dissipation characteristics of silicone rubber are used to study the plasma penetration behavior. The results show that the plasma can indeed penetrate the porous inorganic layer on the surface of the contaminated silicone rubber and treat the surface of experimental samples, which shallows the surface charge trap and accelerates the surface charge dissipation rate. Furthermore, the surface charge dissipation curve of silicone rubber is approximately a double exponential curve through data fitting, which confirms the theory that the charge trap on the surface of silicone rubber can approximately be described as one deep charge trap and one shallow charge trap. Concerned the properties of surface porous inorganic contamination, the results show that the larger the particle size of the porous inorganic contamination materials, the larger the pore diameter of the corresponding contamination layer, which enhances the the plasma penetration effect. Meanwhile, the smaller the contamination density, the shorter the distance for the plasma penetration which also benefit to plasma penetration process. Additionally, The higher the voltage and frequency of AC plasma source, the more high-energy particles the plasma contains, and the stronger its penetration in the porous inorganic contamination layer.