Waterborne epoxy composite coating with long-term corrosion resistance through synergy of MXene nanosheets and ZnO quantum dots

Two-dimensional (2D) MXene nanosheets have emerged as a promising candidate as functional filler for anticorrosion coating. However, the self-stacking of MXene nanosheets and high conductivity limited the long-term anticorrosion ability of the coating. Herein, the ZnO quantum dots (ZnO QDs) decorated MXene hybrid was prepared via electrostatic assembly, which was modified by aminosilane-functionalized with 3-aminopropyltriethoxysilane (ATPES) and used as functional filler for reinforcing the waterborne epoxy coating (WEP) via simple spraying technique. Benefiting from the improved dispersion and synergy of ZnO QDs and MXene nanosheets, the WEP coating exhibited favorable anticorrosion performance. For 0.50 wt% F-MXene@ZnO QDs/WEP composite coating, the impedance remained 1.25 × 108 Ω cm2 (0.01 Hz) after immersing in 3.5 wt% NaCl medium for 30 days, which was three orders of magnitude higher than pure WEP. The EDS analysis and salt spray test strongly supported the long-term corrosion resistance of WEP composite coating. Furthermore, the reasonable anti-corrosion performance of composite coating including the physical barrier and charge neutralization effect was illustrated. This work expands the 2D MXene as a functional filler for enhancing the anticorrosion ability of waterborne epoxy coating.