Durable corrosion resistant and hot water repellent superhydrophobic bilayer coating based on fluorine-free chemicals

Due to their unique interface functions, superhydrophobic materials have a wide range of applications. However, the majority of current superhydrophobic surfaces are designed and manufactured using fluorinated chemical reagents. Moreover, high temperature water droplets with lower surface tension easily pinning to the surface, resulting in interfacial property failures. To overcome these deficiencies, herein we fabricated a superhydrophobic bilayer coating on Q235 carbon steel based on fluorine-free chemicals of polydimethylsiloxane (PDMS) and hexadecyltrimethoxysilane modified aluminum oxide nanoparticles (Al 2 O 3 @HDTMS). Field-emission scanning electron microscopy (FE-SEM), Energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Contact angle meter, and Electrochemical impedance spectroscopy (EIS) techniques were utilized to characterize the constructed superhydrophobic bilayer coating. The results show that the superhydrophobic bilayer coating exhibits non-wetting, anti-fouling and self-cleaning capacities towards various solid and liquid pollutants. The superhydrophobic bilayer coating possesses superior anti-corrosion and weather resisting properties with |Z| 0.01Hz and R ct values increased by more than eight orders of magnitude, withstanding 720 h accelerated salt-spray and 50 days outdoor atmospheric corrosion attack. Furthermore, the superhydrophobic bilayer coating features super-repellency towards water droplets in a wide temperature range (30 ∼ 90 °C) and accompanied with high mechanical stability against continuous sandpaper abrasion and tape-peeling cycles.