| Super-hydrophobic materials gradually began to have more and more researchers in the 1990s.Because of their waterproof,anti-fog,anti-fouling,self-cleaning,oil-water separation and other characteristics,they have been widely concerned by countless scientific researchers.Inspired by the structure of nature's plants and animals with super-hydrophobic functions,such as butterfly wings,lotus leaf surfaces,fly eyes etc phenomenon,the researchers found two characteristics of super-hydrophobic materials:one is that the surface needs to achieve sufficient roughness,similar to the bionic micro-nano structure on the surface of the lotus leaf;the other is to reduce the surface energy of the material surface.The rise of research on super-hydrophobic materials has made many related industries have research value,such as self-cleaning coatings,microfluidic devices,bi°Compatible materials and other fields are highly anticipated.In recent years,researchers have begun to give super-hydrophobic materials more other lateral functions,such as self-healing,tolerance,antibacterial and bacteriostatic properties,fire retardant,electrical conductivity,etc.These lateral functions give the original A single super-hydrophobic material system adds a lot of research value and significance,making the research of super-hydrophobic materials a hot research field,giving super-hydrophobic materials great application prospects and application markets.In this paper,the development background of super-hydrophobic materials is discussed firstly,and then the hydrophobic mechanism of super-hydrophobic coating is analyzed from the micro point of view such as molecular atom.Then,two experimental methods for preparing SiO2 super-hydrophobic coating are introduced,and the related properties are tested,analyzed and discussed theoretically.1.transparent SiO2 super-hydrophobic coatings were prepared by sol-gel pr°Cess using acid tetraethyl orthosilicate(TEOS)as raw material and alkaline catalysis.The surface roughness of the coating is increased due to the formation of layered micro nano structure due to the accumulation and agglomeration of SiO2 nanoparticles.Through the wettability test,the maximum contact angle of the surface can reach 159o,and through the UV transmittance test,the maximum transmittance of the coating can reach 82%,among which the surface transmittance reaching the super-hydrophobic standard can reach more than 70%.FT-IR was used to test the chemical composition and structure of the coating surface.Scanning electron microscope(SEM)was used to observe the surface micro morphology.Different SiO2 content has great influence on the surface roughness.It was found that with the increase of SiO2 content,the surface roughness increases,the contact angle increases,and the transparency decreases.Through the chemical stability and mechanical stability test,it is found that the super-hydrophobic transparent coating has certain wear resistance,high temperature resistance and corrosion resistance,reflecting the excellent stability of the coating.2.By dispersing the existing nano-SiO2 powder in anhydrous ethanol,using°Ctadecyl trichlorosilane(OTS)as the surface modifier,varnish as the hydrophobic modification carrier,and butyl acetate as the solvent,super-hydrophobic transparent composite film was prepared.The wettability test shows that the maximum contact angle is 161o,the highest transmittance is 81%,and the average transmittance is over 70%.The surface chemical structure and composition were characterized by FTIR.Scanning electron microscopy(SEM)was used to observe the surface morphology,and it was found that the surface roughness was greatly affected by the amount of SiO2.The results of acid and alkali resistance test,high temperature resistance test and adhesion test show that the superhydrophobic composite film can withstand 250°C high temperature and strong acid and alkali solution environment with p H from 2 to 14.Through adhesion test,it is found that the coating has super adhesion,and the ISO grade is up to grade 1. |
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