Fabrication of self-healable superhydrophobic polyurethane coating based on functional CeO2 nanoparticles for long-term anti-corrosion application

Abstract

Corrosion of mild steel is everywhere and eco-friendly and efficient corrosion protection strategies deserve to be popularized. Superhydrophobic coatings are available for metal corrosion protection, but the limited-service life restricts their development. Here, we prepared environmentally friendly coatings with long-term corrosion resistant using a simple spray strategy. A two-layer superhydrophobic self-healable composite coating was prepared by spraying WFPU and fluoroCeNPs onto mild steel. The bottom WFPU prevents corrosion by corrosion inhibitor CeO2 and repairs physical scratches by heating. The upper layer of fluoroCeNPs prevents the penetration of corrosive media by forming an air cushion at the solid-liquid interface. The combination of low surface energy and micro/nano hierarchical structure allows WFPU/fluoroCeNPs coating to exhibit superhydrophobicity and low adhesion, with a water contact angle of 157° and adhesion force 12.8 μN. In addition, WFPU/fluoroCeNPs coating exhibit excellent corrosion resistance, with an impedance modulus of 7.2 × 109 Ω cm2 at low frequency (f = 0.01 Hz), which remains at 108 Ω cm2 after 60 days in 3.5 wt% NaCl solution. After self-healing, the material can recover to its original state, both in terms of mechanical and corrosion protection properties. This new composite coating, which combines environmental protection, energy saving and remarkable effects, has a wide application value for the protection of metal against corrosion.