Anti-icing Performance Of Solid Surface Based On Superhydrophobic Modification

Life and economic losses caused by icing and frosting accidents are tremendous.Freezing/frosting resistant surfaces are attracting extensive attention.Presently,mechanical deicing or spraying anti-freezing reagent is energy consumption and generally brings environmental pollution,which can not fundamentally solve the problem.Inspired by lotus leaf and water strider of nature,superhydrophobic surface has been found possessing some extent resistance to water freezing due to high icing nucleation energy barrier and spontaneous motion phenomenon of condensate droplets.In the first part of this research,we constructed Cu O nanoneedle structures on copper substrate by wet oxidation etching method.After low surface energy modification,superhydrophobic surface with high water contact angle and low sliding angle was obtained.Condensate droplets on such surface has very strong spontaneous motion ability,e.g.,condensate droplets can be self-propelled off the surface.When the surface temperature was-10 o C and RH was 60%,delayed frosting phenomena(up to 4 h)was observed.After introducing a slight wind and simultaneously eliminating edge effect,the superhydrophobic surface showed factual anti-freezingproperty(-10 o C,?12 h).In practical application,it is necessary to optimize production methods to prepare superhydrophobic surface largely.We first mixed nano Si O2 particles and fluorine-containing sol and then obtained superhydrophobic nano coat by different coating method.When the nano Si O2 sol prepared by Stober method was joined into fluoride silicone sol and was dip coated on the glass slide,superhydrophobic surface with monolayer nano Si O2 particles was obtained.Condensate water drops on such coat surface(-10 o C)held liquid state up to 1 h and 2 h at static and dynamic(with slight wind),respectively.Fast coalescence and self-propelled motion was also observed.Aimed at practical application,commercial nano Si O2 particles were dispersed in above fluorine silicon sol and mixed into epoxy resin emulsion,superhydrophobic Si O2 coat was obtained by simple spraying process.The coat is economic,environmental friendly,and can be cross linked or dried at room temperature.The binding force with the substrate was high.The coating showed freezing resistance at-15 o C to mixture of ice and water but hanged ice bead under-20 o C.This demonstrated the coating has a certain extent resistance to ice rain and could be used in south of China in winter,but not in northeast of China in winter,e.g,anti-icing for high speed train.