Study on the Construction and Anti-Corrosion Properties of Mechanically and Chemically Stable Superhydrophobic Coatings

Abstract

The superhydrophobic coating can effectively prevent the intrusion, adhesion and condensation of water-containing corrosive media on the surface. However, the poor mechanical and chemical stability of traditional superhydrophobic coatings significantly limits their application in complex and harsh environments. In this study, a superhydrophobic PDMS-EP@SiO2-GO coating was formed on the surface of Q345 steel sheets by using a composite substrate of graphene oxide(GO) and nano silicon dioxide(SiO2) with polydimethylsiloxane(PDMS) and epoxy resin(EP), combined with spraying technology. The superhydrophobic, self-cleaning, anti-fouling, mechanical wear resistance, chemical corrosion resistance and anti-corrosion properties of the coating were studied. Results showed that the water contact angle of PDMS-EP@SiO2-GO was 166.57°, and the sliding angle was less than 3°. Due to the strengthening effect of GO on the coating substrate, the coating maintained a contact angle of more than 155° for liquids with water temperatures ranging from 20 ℃ to 100 ℃ and a contact angle of more than 160° for acidic/alkaline solutions. The sliding angle was less than 4° under the above conditions. After sandpaper friction(total friction length of 40 m) and 30 cycles of tape-peeling tests, the coating still exhibited good superhydrophobic ability, with the contact angle remaining above 152°. In addition, PDMS-EP@SiO2-GO, with excellent water resistance, demonstrated good anti-fouling and self-cleaning properties. In terms of corrosion protection, the lowest frequency impedance of PDMS-EP@SiO2-GO increased by an order of magnitude, and the charge transfer resistance increased by two orders of magnitude, showing excellent corrosion resistance. PDMS-EP@SiO2-GO addressed the problem of weak mechanical and chemical stability in traditional superhydrophobic coatings and enabled the persistent protection of the metal substrate. The as-prepared superhydrophobic coating, with good practicability, contributes to the safe and reliable service of mechanical equipment throughout its life cycle.

Keywords

• superhydrophobic coating; nano silicon dioxide; mechanical stability; chemical stability; anti-corrosion and wear resistance