Preparation And Properties Of Environmentally Friedly Waterborne Superhydrophobic And Superamphiphobic Coatings

Inspired by the“lotus effect”in nature,preparation and applications of the bioinspired superhydrophobic and superamphiphobic coatings are of great interest in academic and industrial areas.Superhydrophobic and superamphiphobic coatings are promising materials in various fields including self-cleaning,oil/water separation,anti-icing and anti-corrosion,because of their excellent superhydrophobicity and superamphiphobicity.However,their real-world applications are hindered by some main bottlenecks,such as pollutive preparation methods and poor mechanical stability.Thus,it is very important to prepare environmentally friendly and mechanically durable superhydrophobic and superamphiphobic coatings.Here we report fabrication of totally waterborne and durable superhydrophobic and superamphiphobic coatings.The main results are shown below.First,hexadecyl polysiloxane?HD-POS?modified SiO₂?SiO₂@HD-POS?aqueoussuspensionwassynthesizedbyhydrolyticcondensationof hexadecyltrimethoxysilane and tetraethoxysilane?TEOS?in the presence of HCl.Subsequently,the PU/SiO₂@HD-POS coatings were fabricated by in turn spray-coating a polyurethane?PU?aqueous solution and the SiO₂@HD-POS aqueous suspension onto glass slides.The as-prepared PU/SiO₂@HD-POS coatings displayed many excellent properties.The coatings had excellent superhydrophobicity with a water CA of 163.8°and a SA of 3.7°.The coatings showed exceptional mechanical stability.After abrasion against sandpaper and tape-peeling for 200 cycles,the coatings were still superhydrophobic.The coatings were also chemically and thermally stable.The coatings showed excellent resistance in various corrosion solutions and organic solvents or under UV irradiation.The coating had an excellent self-healing capability against O₂ plasma damage and could retain its superhydrophobicity with a water CA of 153.7°after nine cycles.The coating exhibited good anti-icing performance in an extremely freezing weather?outdoor environment,-15°C,relative humidity=54%?.In the static experiments,the coating can delay icing by ca.30 min.In the dynamic experiments,there was no ice formed on the coating during the whole process of the experiment.Superamphiphobic coatings are not only superhydrophobic but also superoleophobic,which are different from superhydrophobic coatings.Thus,the surface energy of superamphiphobic coatings is lower and the preparation of superamphiphobic coatings is more difficult,but their applications are more extensive.Based on the totally waterborne PU/SiO₂@HD-POS superhydrophobic coatings,the PU/SiO₂@fluoro-POS superamphiphobic coatings were fabricated by modification of SiO₂nanoparticlesviahydrolyticcondensationof1H,1H,2H,2H-perfluorodecyltriethoxysilane and TEOS in water.The as-prepared PU/SiO₂@fluoro-POS coatings exhibited many excellent properties.The coatings had excellent superamphiphobicity with water CA of 170.5°and SA of 1.0°,n-hexadecane CA of 163.8°and SA of 7.0°.The PU/SiO₂@fluoro-POS coatings showed exceptional mechanical stability.The coatings were still superamphiphobic after abrasion against sandpaper for 200 cycles and tape-peeling for 200 cycles or water jetting for 60 min.The coatings show excellent resistance in various corrosion solutions and organic solvents or under UV irradiation,displaying highly chemical stability.The PU/SiO₂@fluoro-POS coatings also exhibited excellent thermal stability.The coatings can withstand heat treatment at temperature of 400?in air or boiling water.Additionally,the coatings exhibited good anti-icing performance in an extremely freezing weather?outdoor environment,-10°C,relative humidity=48%?.In the static experiments,the coating can delay icing by ca.16 min.In the dynamic experiments,no ice was formed on the coating during the whole process of the experiment.In this study,totally waterborne superhydrophobic and superamphiphobic coatings with excellent stability have been prepared.The comprehensive stability of the coatings was investigated,and their applications for anti-icing in actual environment are explored.The main bottlenecks hindering practical applications of superhydrophobic and superamphiphobic coatings have been broken.This study sheds a new light on preparation of environmentally friendly superhydrophobic and superamphiphobic coatings.