Waterborne superhydrophobic coating with abrasion and corrosion resistant capabilities

Superhydrophobic materials have been extensively exploited for corrosion protection because of their unique non-wetting properties, but restricted by the complicated fabrication process, fluorinated chemicals usage, weak interfacial binding force, low hardness, and poor abrasion/scratch resistance. In this paper, we designed a waterborne superhydrophobic coating based on modified Al2O3 nanoparticles (M-Al2O3) and waterborne epoxy resin through a versatile spray-coating approach. When the mass ratio of epoxy/M-Al2O3 was 1.5, the coating features both superhydrophobic properties (water contact angle ∼ 150.8 ± 0.6° and sliding angle ∼ 4.9 ± 0.2°) and optimal abrasion-resistant stability. The coating can maintain its water-repellent superhydrophobicity after 90 abrasion cycles and 120 tape-peeling cycles, indicating reinforced interfacial robustness. Moreover, the coating exhibits excellent self-cleaning, anti-fouling, and corrosion-resistant behaviors with greatly enhanced charge transfer resistance (Rct) and lowest frequency impedance values (|Z|0.01Hz). The corrosion inhibition efficiency of the original coating, coating after 90 abrasion cycles and coating after 120 tape-peeling cycles were 99.99 %, 97.54 %, and 97.52 % respectively, confirming a durable anti-corrosion stability. In addition, the coating retains its superhydrophobic properties after a 6 H pencil hardness test and knife scratch test, which demonstrates its robustness and stability against mechanical damage.