Research And Application On Anti-condensation Failure Mechanism Of The Armored Superhydrophobic Surface

Superhydrophobic materials have broad application prospects in industry,military,and biomedicine.However,the problem of superhydrophobic performance failure of traditional microstructure superhydrophobic materials due to condensation in high supercooling and high humidity environments is becoming the obstacle to practical application of the superhydrophobic materials.In recent years,research on superhydrophobic materials has focused on improving oil-water separation efficiency,super-liquid-repellent ability,and mechanical stability,and relatively little research has been done on super-hydrophobic anti-condensation failure ability.In this thesis,one kind of method to improve the anti-condensation performance of superhydrophobic materials through rational surface design is proposed,and the anti-condensation failure performance of the prepared superhydrophobic materials is tested under high subcooling and high humidity environments.The specific research work is summarized as follows:(1)In this thesis,a hydrophilic silicon-based inverted quadrangular pyramid microstructure was introduced into the surface of nano-superhydrophobic silica,and an armor with long-term anti-condensation failure performance was obtained by coupling different properties of materials such as thermal conductivity,surface energy,and solidliquid adhesion.the parental surface.Combined with material structure characterization,contact angle change,and adhesion measurement,the condensation and nucleation of water vapor on hydrophilic microstructures is highly selective through the design of the area fraction.The long-term anti-condensation failure ability of the armored amphiphilic surface was experimentally observed,and the phenomenon of continuous and repeated droplet nucleation-growth-merging-detachment-re-nucleation of condensed droplets on the superhydrophobic surface was recorded.The experimental results show that,The armored amphiphilic surface has the ability to maintain its own superhydrophobicity for at least 36 h at room temperature of 25 °C,relative humidity of70%,and condensation temperature of 1 °C.(2)In this thesis,five superhydrophobic surfaces with different material structures including the armored amphiphilic surface,superhydrophobic photoresist column,superhydrophobic super-dry coating,superhydrophobic copper hydroxide nanowires and superhydrophobic copper oxide nanosheets,and they were subjected to anti-heat droplet adhesion ability test,hot droplet bouncing ability test,hot steam test and hot droplet continuous impact test respectively.Combined with the experimental results,the reasons for the differences in the ability of different superhydrophobic surfaces to resist condensation failure in different environments can be obtained,which has certain significance for analyzing the influence of the surface properties and structural scales of materials on the ability to resist condensation failure.Compared with several other superhydrophobic surfaces,the experiments show that,the armored amphiphilic surface has the most long-term stability and resistance to condensation failure,which proves that the superhydrophobic state can indeed be maintained by the design of the continuous hydrophilic microstructure introduced into the nanoscale superhydrophobic surface.Long-term stability in high humidity and high subcooling environments,coupling differences in thermal conductivity,surface chemistry,and solid-liquid adhesion that affect surface-to-interface properties to the same surface to achieve high spatial selectivity for condensation nucleation can be used as a strategy to the problem of condensation failure on superhydrophobic surfaces.