Synthesis Of Fluorinated Finishing Agent And Preparation Of Superhydrophobic Structure

There are many superhydrophobic phenomena in nature,such as lotus leaf,water strider and rice leaf.Super hydrophobic surface means that the water contact angle of solid surface is greater than 150 degrees and the rolling angle is less than 10 degrees.Super hydrophobic surfaces have many unique properties,such as self-cleaning,anti-corrosion,anti-icing,oil-water separation and drag reduction,which can be applied in many fields and attract wide attention.Up to now,there are many methods to prepare superhydrophobic surface,including template method,vapor deposition method,anodic oxidation method,layer-by-layer self-assembly method,etc.But most of these methods require complex processes and expensive equipment and instruments,which are difficult to produce on a large scale.Therefore,it is necessary to study a simple,effective and easy-to-implement method to prepare superhydrophobic surface.Perfluoropolyether aminosiloxane finishing agent was synthesized from perfluoropolyether acyl fluoride,anhydrous methanol and 3-aminopropyl triethoxysilane(KH550).Its structure was characterized by infrared spectroscopy.The water contact angle can be increased from 64.1 to 114.1 degrees and the oil contact angle can be increased from 29.7 degrees to 63.9 degrees after spraying on the glass surface.The superhydrophobic surface of aluminium alloy was prepared by ammonium fluoride etching method and hydrothermal etching method.The water contact angle of the superhydrophobic surface prepared by ammonium fluoride etching method was 152±2°,and the rolling angle was 25 ± 3°.The water contact angle of the superhydrophobic surface prepared by hydrothermal etching method was 155±1.5°,and the oil contact angle was 145.6±1.2°,and the rolling angle was 2±1°.The superhydrophobic property of the superhydrophobic surface The polarization curves showed that the corrosion potential of the superhydrophobic surface prepared by ammonium fluoride etching increased from 0.872V to-0.714V,the corrosion current density decreased from 4.34*10-7(A*cm-2)to 5.77*10-9(A*cm-2),and the corrosion current density decreased by two orders of magnitude.The corrosion potential of the superhydrophobic surface prepared by hydrothermal etching increased from-0.885V to-0.632V.The corrosion current density decreases from 6.03*10-7(A*cm-2)to 2.82*10-2(A*cm-2).The corrosion current density decreased by three orders of magnitude,and the corrosion resistance improved.The results of self-cleaning and stability test show that the superhydrophobic surface prepared by ammonium fluoride etching has good self-cleaning and thermal stability,chemical stability and mechanical stability are poor,and the superhydrophobic surface prepared by hydrothermal etching has good self-cleaning,thermal stability,chemical stability and mechanical stability.Fluorine-containing coupling agents(FTES)were prepared from trifluorooctanol,methacrylic acid and KH550.The structure was characterized by IR.The super hydrophobic nano silica sol coating was prepared on the surface of different substrates by sol-gel method.The water contact angle of the coating was 152±1.8°.After 8 weeks at room temperature,the water contact angle of the coating decreased by 2°.The results of self-cleaning and stability test show that the coating has good self-cleaning performance,acid and salt resistance and thermal stability..