Preparation Of Glass-based Transparent Superhydrophobic Coating By Sol-gel Method

Super-hydrophobic coating has many unique properties.Applying it to glass surface to prepare glass-based transparent superhydrophobic coating has a wide range of application prospects.However,in the actual application at this stage,there are still several problems.For example,the poor coating adhesion;poor coating stability,low acid and alkali resistance;the complicated preparation method and strict equipment requirements.The purpose of this paper is to prepare a glass-based transparent superhydrophobic coating that has good adhesion to the substrate,good durability,simple preparation process,and can meet the requirements of outdoor operations.The main research contents and conclusions are as follows:(1)Through the sol-gel process,ethyl orthosilicate was used as the silicon source,ammonia water was used as the catalyst,and the monodisperse SiO2 sols with particle diameters ranging from 10-50nm and 50-100nm were prepared by adjusting the amount of reactants and reaction conditions.The experimental results show that the prepared nano-SiO2 sol has controllable and uniform particle size,and good dispersibility.With the increase of the amount of ammonia,the particle size of the SiO2 sol increases;with the increase of the amount of TEOS,the particle size of the SiO2 sol increases;with the increase of the temperature,the particle size decreases;with the increase of the reaction time,the particle size shows a trend of first increasing and then decreasing.(2)The SiO2 sol particles with particle sizes ranging from 10-50nm and 50-100nm were modified respectively by silane coupling agents KH560 and KH550,so that the surface of SiO2 particles with different particle sizes were equipped with epoxy groups and amino groups.Then,the modified two kinds of particles were mixed,and the group reaction occured to form chemical bonds.The composite structure SiO2 particles were obtained,which realized the bionic construction of the lotus leaf-like surface graded rough structure.The experimental results show that the silane coupling agents KH560 and KH550 are fully grafted to the surface of nano-SiO2,and small-sized particles are attached to the surface of large-sized particles.The dispersion between the composite particles is good,and there is no agglomeration phenomenon.The best combined size of the two SiO2 sol particles is 40nm+80nm,and the best mixing volume ratio is 1:1.(3)The modified composite structure SiO2 sol was coated on the surface of the treated glass substrate by dipping and pulling,and then was treated with fluorosilane(FAS)to obtain a transparent super-hydrophobic coating.The results show that the maximum contact angle of the coating reachs 155°,the minimum rolling angle is 3°,and the transmittance of the coating in the visible light range is maintained above 90%.As the amount of silane coupling agent increases,the hydrophobic effect of the coating increases,but the transparency decreases.The optimal silane coupling agent concentration is 2.0%.The best immersion concentration when treating samples with fluorosilane solution is 1.0%,the best immersion time is 1h,the best immersion temperature is 25?,and the best number of coatings is 4 times.The coating has good adhesion to the substrate,good self-cleaning ability and stability,excellent acid resistance and ultrasonic resistance,good alkali resistance and abrasion resistance.