The fabricated coatings exhibit high contact angles and a characteristic redness due to high temperature treatment of the epoxy.
The coatings are completely opaque due to the ultra-high roughness illustrated in SEM images (Fig. 2). The uniquemethod of spray coating the hardening epoxy onto hot surfaces results in the distinctive morphology required for superhydrophobic properties.
The ability to rapidly drive off the solvent while allowing the epoxy to harden gives rise to a multiscale, rough surface (Fig. 3). Enhanced by embedded silica nanoparticles to add a nano-rough texture, coated samples achieve high contact
angles and lowroll-off angles via the entrapment of air inmultiscale cavities.
Despite the high roughness, the coating retains its adhesion to the substrate as well as resistance to abrasive force. The high durability of the coating is demonstrated by remaining superhydrophobic after several mechanical wear tests.