Fabrication And Anti-icing Properties Of Superhydrophobic Surfaces Based On Silica With Low Surface Energy

The adhesion and accumulation of ice on the solid surface could result in traffic interruption,communicating destruction,loss of power and damage of equipment related to aviation,telecommunication,electricity and transportation.Therefore,it is of great significance to design and construct a surface for application in anti-icing.A large number of studies have shown that the superhydrophobic surface was one of the most effective strategies to inhibit the formation of ice and reduce the accumulation of ice because of its unique micro-nano structure,which could trap the air layer and thus reduce the effective contact area between droplets and the surface.However,these superhydrophobic surfaces usually showed poor stability,restricting their real applications.Under external forces,the superhydrophobic surface was easily damaged and then its hydrophobicity was reduced,thus affecting its anti-icing property.In addition,it is still a contradiction between enhancing superhydrophobicity and suppressing growth of ice nuclei for the superhydrophobic surface.Therefore,it is difficult to prepare the superhydrophobic surface with good anti-icing property at ultra-low temperature?<-30.0°C?.So,superhydrophobic surfaces based on SiO₂nanoparticles with low surface energy were prepared to improve stability and anti-icing property at ultra-low temperature.Compared with traditional superhydrophobic surfaces,these superhydrophobic surfaces did not only show good hydrophobicity and structural stability,but also exhibited excellent anti-icing performance.The research results and innovations are as follows:?1?Flower-like SiO₂ particles with low surface energy and different particle sizes?300.0nm,450.0 nm and 600.0 nm?were prepared by microemulsion method.The effect of particle size on its superhydrophobic and anti-icing properties was investigated in detail.The hydrophobicity of flower-like SiO₂ particles firstly increased and then decreased with increasing in particle size,while the anti-icing performance decreased continuously with increasing in particle size.For the flower-like SiO₂ particles with size of 450.0 nm,it showed the best superhydrophobicity?CA=163.7°?.However,the flower-like SiO₂ particles with size of 300.0 nm showed the best anti-icing performance.The water droplets could roll off the surface rapidly and the freezing time of the water droplets was extended to 564.0 s at-25?.These results indicate that the anti-icing performance of the superhydrophobic surface is not only affacted by its hydrophobic performance,but also depends on its surface structure.Under similar hydrophobic performance,the surface with smaller micro-nano structure showed better anti-icing performance.?2?The spherical SiO₂ nanoparticle dispersion solution was firstly prepared,and was sprayed on the surface of the pre-cured epoxy resin to form superhydrophobic surfaces with double-layer self-assembly structure.The effect of the concentration of the dispersion solution?1.0 wt%,2.0 wt%,5.0 wt%and 10.0 wt%?on the structure and anti-icing performance of the superhydrophobic surfaces were investigated in detail.The anti-icing mechanism of the superhydrophobic surfaces were also investigated by a high speed video and thermal infrared imaging equipment.The results showed that the superhydrophobic surface prepared by 5.0wt%OTS-SiO₂ dispersion solution exhibited high hydrophobic performance?173.1°?and extremely low rolling angle?0°?.In addition,the superhydrophobic surface also showed excellent mechanical durability,the contact angle was still above 165°after 50 abrasion cycles.At the same time,the superhydrophobic surface still exhibited excellent anti-icing performance in an ultra-low temperature environment?-40°C?,in which the time of water droplets complete freezing was extended to 372.0 s.This excellent anti-icing performance is attributed to excellent superhydrophobic properties and surface nanostructures.?3?The SiO₂ nanoparticles with low surface energy were dispersed into the fluorocarbon polymer solution containing TiO₂ particles.Above mixture was sprayed on substrate,forming superhydrophobic surfaces based on polymer nanocomposite.The effect of the doping amount of SiO₂ nanoparticles?0 wt%,15 wt%,20 wt%and 25 wt%?on its surface structure and properties of polymer nanocomposite was invesigated in detail.When the content of SiO₂nanoparticles was 20 wt%,the polymer nanocomposite exhibited excellent superhydrophobicity?166.3°?,mechanical and thermal stability.Its adhesive strength and impact strength were about 8.9 MPa and 71.0 kg·cm,respectively.In addition,its hydrophobicity slightly changed under 30 bending cycles,50 abrasion cycles and 300?high temperature treatment.Moreover,the polymer nanocomposite also exhibited excellent anti-icing stability.After 55 icing/melting cycles,the polymer nanocomposite still exhibited superhydrophobic properties?153.6°?and good anti-icing performance.