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Smart water-borne epoxy coating with MXene nanocomposites enables self-healing and advanced corrosion protection
A Chinese research team has developed a waterborne epoxy coating based on MXene nanocomposites with multistage self-healing functionality. The coating combines barrier and self-repair mechanisms to achieve superior corrosion resistance and mechanical performance.
MXene-based two-dimensional nanomaterials offer great potential for functional coatings, but their tendency to self-aggregate limits their dispersion stability in polymer matrices. Researchers led by Junjie Cao have overcome this limitation with a three-step construction strategy, resulting in a smart waterborne epoxy coating with exceptional corrosion resistance.
Mesoporous polydopamine (mPDA) spheres were prepared via a nanoemulsion assembly process and attached to Ti₃C₂Tₓ MXene nanosheets through interfacial self-assembly. Sodium molybdate (Na₂MoO₄) was then incorporated into the mPDA pores, forming a hierarchical MXene@mPDA@Mo (MPMo) nanocomposite.
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Multistage self-repair through chelation and passivation
The MPMo nanohybrids were dispersed in a waterborne epoxy resin (WEC) matrix. Electrochemical impedance spectroscopy revealed a corrosion resistance (Rc) of 7.26 × 10⁸ Ω·cm² after 60 days of immersion in 3.5 % NaCl solution – three orders of magnitude higher than that of pure epoxy.
The self-healing capability was confirmed by EIS measurements on scratched coatings, 700 h salt spray testing, and SEM-EDS and XPS analyses. Mechanically, the coating achieved an adhesion strength of 6.59 MPa and a tensile strength of 36.46 MPa, outperforming conventional epoxy coatings. UV ageing and thermal cycling further demonstrated its durability.
Through the synergistic combination of MXene architecture, metal chelation by polydopamine, and anodic passivation by molybdate, this approach provides a promising pathway toward next-generation self-healing, waterborne anticorrosive coatings.
Source: Cao, J. et al. Construction of waterborne epoxy smart anti-corrosion coating based on mPDA/Ti₃C₂Tₓ nanocomposites – Synergistic barrier effect and self-repair mechanisms. Prog. Org. Coat. 207, 109427 (2025).
