Superhydrophobicity, conductivity and anticorrosion of robust siloxane-acrylic coatings modified with graphene nanosheets

Abstract

The effects of low-cost graphene nanosheets in organic coatings were investigated. The hydrophobic organic siloxane-acrylic resin was synthesized by solution polymerization of acrylic monomers while the graphene nanosheets were modified using fluorosilane, and applied on LY12 aluminum substrate via spraying and a two-step coating system. The superhydrophobic, conductive, anticorrosion, self-cleaning, oleophilic and physical behaviors were comprehensively characterized. The results obtained revealed that addition of modified graphene increases the surface conductivity (≥ 2 μS/cm) and the water contact angle (≥ 152°) with low sliding angle (≤ 7°). The polarization measurement showed a positive shift in the corrosion potential signifying an inhibition of the cathodic reaction. Also, the two-step coated sample gave a good corrosion protection barrier as further confirmed by the electrochemical impedance parameters. The coating revealed good resistance to dirt adhesion, and its superhydrophobic-oleophilic property offered a promising application in oil-water separation. The physical integrity of the coatings was not extensively affected including after 120 days of outdoor exposure to snowing, de-freezing and surface wetting.