Superhydrophobic nanocomposite coatings with photoinitiated three-dimensional networks based on reactive graphene nanosheet-induced self-wrinkling patterned surfaces

Bionic superhydrophobicity including high contact angle, low sliding angle and nonstick property, combined with both strong pH and ultraviolet (UV) resistance, is difficult to simultaneously achieve for large-scale preparation of superhydrophobic surfaces by blending polymer with a nonreactive inorganic nanofiller. A series of high pH and UV-irradiation-resistant superhydrophobic nanocomposite films were prepared through UV-light-assisted chemical cross-linking among ternary components under nitrogen protection. Ethoxylated bisphenol A diacrylate, 2-(perfluorooctyl) ethyl acrylate, reactive thiol-coupled graphene nanosheets and photoinitiator were evenly mixed, followed by UV-irradiation curing. Abundant 3D networks could be formed. A robust self-wrinkling surface morphology was formed due to a UV-curing-induced inner tension in the composites, 2D morphology-induced flexibility for graphene nanosheets and fluorine-bearing component-induced phase separation at the wetted surfaces. High roughness and use of the fluorine element endows the surfaces with superhydrophobicity and oleophobicity. A favorable nonstick performance was obtained. Superhydrophobicity could be maintained despite changing the film-forming substrate, pH of soaking solutions from 1 to 12, or use of a prolonged UV-irradiation time reaching 120 h. Therefore, both superhydrophobicity/oleophobicity and strong pH/UV resistance are finely balanced. This work might open up the way for large-scale fabrication of promising superhydrophobic surfaces.