Fabrication of robust and repairable superhydrophobic coatings by an immersion method

The development and practical application of superhydrophobic coatings are mainly limited by complex fabrication processes and fragile surface structures. Meanwhile, it is difficult to overlay superhydrophobic coatings on the internal surfaces of special shaped constructions. To handle these problems, the simple two-immersion method was adopted and a kind of novel repairable superhydrophobic surface was successfully fabricated with the mixture of fluorocarbon resin and nanometer silicon dioxide. The technological parameters were discussed and a serious of robustness tests were carried out on the optimized coating. The results indicated that the surface maintained superhydrophobic after 1600 cm sandpaper abrasion and still repelled water after 20,000 cm abrasion. Also, water and sand impact tests were put into effect to prove this coating can endure harsher environment. Through further investigation, it was found that this coating had a repairable ability against mechanical damage via simply immersed again. In addition, the coating exhibited ideal properties at different pH levels. As the porous foam test revealed, this superhydrophobic coating is expected to be used on the inner surface of irregular structures.