A novel cerium organic network modified graphene oxide prepared multifunctional waterborne epoxy-based coating with excellent mechanical and passive/active anti-corrosion properties

Effectively reducing microdefects and endowing coatings with active protection are critical factors in prolonging the service life of coatings. Herein, a novel ceria nanoparticle decorated cerium organic network (GO-CN/CON-U) is in-situ prepared on graphene oxide (GO) via a simple one-step method. Then, a multifunctional coating is obtained by introducing GO-CN/CON-U into the epoxy resin matrix. The coating surprisingly exhibits exceptional mechanical properties and hydrophobicity attributing to the optimized crosslinking degree, compactness, and toughness due to the interaction between composite materials and epoxy resin, while its sustained anti-corrosion performance (around 109 Ω·cm2) also displays three orders of magnitude higher than that of pure epoxy coating (less than 106 Ω·cm2) even after 60 d of immersion in the aggressive media. An active protective mechanism was further proposed according to the UV–Vis and microelectrochemical test results, revealing that a shielding film can be promptly formed on the surface of Q235 steel when damage occurs against the attack of aggressive ions due to the release of Ce3+/Ce4+ and organic inhibitors from GO-CN/CON-U under acidic responsiveness. In brief, the present work provides a simple but attractive strategy for the preparation of long-lasting multifunctional protective coatings.