Preparation Of Silicone Rubber Superhydrophobic Surface And Its Flashover Performance Under Condensation Condition

At present,widely used in electrical insulation of silicone rubber materials,the surface is prone to condense water droplets and induce the corona discharge to cause the deterioration of the silicone rubber,eventually leading to surface flashover.The superhydrophobicity material on whose surface the water droplets was easily roll off has excellent water repellent properties,even in harsh environmental conditions,it is difficult to form a continuous water film on the surface.It has important scientific significance and application value to improve the application effect of superhydrophobic coating in electrical insulation.In this paper,the purpose of modifying the existing silicone rubber material to superhydrophobic is proposed,and the hydrophobicity stability,electrical properties,power frequency and surface flashover,condensation characteristics and antipollution flashover characteristics of the superhydrophobic surface are studied.The main contents of the paper are as follows:(1)The hydrophobicity,microstructure,composition and surface energy of fluorinated modified silicone rubber were analyzed by direct fluorination treatment of silicone rubber composite insulators.The results show that direct fluorination of the surface of the silicone rubber can make its surface have superhydrophobic properties.Through the morphological analysis proved that the direct fluorinated silicone rubber can produce a micro-nano composite rough structure.The surface composition test results show that the direct fluorinated silicone rubber can introduce fluorine elements with low surface energy into its surface.Direct fluorination was found to reduce the surface energy of the material by calculating the surface energy.The insufficiency of the direct fluorinated silicone rubber to prepared a superhydrophobic surface was analyzed and illustrated.(2)The common RTV silicone rubber coating mainly uses polydimethylsiloxane as the substrate and nanopariticles as the filler.This paper proposes a method for preparing polydimethylsiloxane filled with nanosilica particles modified with fluorosilane to prepare superhydrophobic coating with micro-nano composite rough structure.The microstructure,chemical composition and hydrophobic stability and dielectric properties of the coating were analyzed.The experimental results show that the prepared superhydrophobic coating has micro-nano composite rough structure,but also has excellent hydrophobic stability and insulation properties.(3)With fluorosilane-modified superhydrophobic coating and common RTV silicone rubber coating as the research object,the effects of temperature and tilt angle on the surface condensation characteristics of these coatings were investigated.The condensation behavior of water droplets was recorded by optical microscopy.The surface condensation appearance characteristics of the fluorosilane-modified superhydrophobic coating and the common RTV silicone rubber coating were analyzed.and the number of condensation droplet movements was counted.Finally,the coating surface coverage rate of the coating was calculated by software.The experimental results show that compared with the common RTV silicone rubber coating,the condensation droplets on the surface of fluorosilane-modified coating show a spherical shape and the condensation water droplets on the surface are easy to roll,making the superhydrophobic coating modified by fluorosilane.The surface of the layer continuously forms a new dry zone,which reduces the amount of condensation on the superhydrophobic surface and helps to improve the moisture and flash performance of the insulator.(4)The test investigated the wet flashover voltage of superhydrophobic coating under different droplet coverage rates,the water repellency of the coating surface under different levels of soiling,and the superhydrophobic coating and common conditions under wet conditions.The common RTV silicone rubber coating and blank glass surface flashover characteristics.The experimental results show that the flashover voltages of the saturated and wet superhydrophobic coatings are basically the same under different tilt angles;the hydrophobic properties of the superhydrophobic coatings remain hydrophobic under different conditions;compared to common RTV silicone rubber coatings and blank glass,fluorosilane-modified superhydrophobic coating with high flashover voltage,low leakage current,in which fluorosilane-modified superhydrophobic coating surface has excellent hydrophobic properties,is the main reason for its high insulation properties.The above studies show that the method of preparing superhydrophobic surface by direct fluorinated silicone rubber is insufficient,but the superhydrophobic coating is prepared by filling polydimethylsiloxane with fluorosilane-modified nano-silica nanoparticles.The coating not only has well insulation performance but also has a good effect of inhibiting condensation.It has important reference value for the moisture-proof and flashover performance of transmission lines under conditions of high humidity and low temperature.