In situ growth of flower-like ZnO onto graphene oxide for the synergistically enhanced anti-corrosion ability of epoxy coating

Two-dimensional graphene oxide (GO) has shown the favorable candidate as functional filler for enhancing the anticorrosive performance of epoxy coating, but its poor dispersion and low antimicrobial ability limited the further application in complex corrosive environment. To overcome these obstacles, a two-dimensional GO-based antimicrobial anticorrosion epoxy composite coating was developed via synergy of graphene oxide and zinc oxide. To achieve this goal, the flower-like ZnO with antimicrobial activity was situ grown on the surface of graphene oxide by hydrothermal route, which was further modified via the dopamine triggered chemical cross-linking with polyethyleneimine (GO-ZnO@DP). Thanks to the good dispersion and the excellent physical barrier property of the GO-ZnO@DP functional filler, the epoxy composite coating exhibited superior ability of corrosion resistance. With the addition of 1.0 wt% GO-ZnO@DP functional filler (G2/EP), the low frequency impedance modulus |Z|0.01Hz reached 1.57 × 109 Ω cm2 after immersion in 3.5 wt% NaCl medium for 30 days. Meanwhile, due to the introduction of flower-like ZnO, the composite coating exhibited the enhanced antibacterial properties toward the inhibitory experiment of E. coli. Besides, the results of salt spray test, EDS analysis, and mechanical properties strongly supported the long-term corrosion resistance of epoxy coating, which shows promising application of metal protection in the complicated corrosive environment.