News Coatings Technologies
Smart nanofiller merges self-healing and anticorrosive functions
A novel core-shell nanofiller combining graphitic carbon nitride, a dynamic disulfide-rich polymer shell and benzotriazole enables epoxy coatings with long-term anticorrosive protection and photothermally triggered self-healing. The system offers a dual-action approach for the protection of copper substrates.
Protecting copper substrates against corrosion while enabling autonomous repair remains a key challenge for advanced coating systems. A recent study introduces a core-shell nanofiller strategy that combines active corrosion inhibition with intelligent self-healing functionality in epoxy resin (EP) coatings. Graphitic carbon nitride (g-C3N4, CN) was selected as the core, onto which a mesoporous poly(dopamine-cystamine) (P(DA-CA)) shell rich in dynamic disulfide bonds was constructed by interfacial copolymerisation in an emulsion system.
Benzotriazole (BTA), a well-established corrosion inhibitor for copper, was subsequently loaded into the mesoporous channels of the shell, yielding the final P(DA-CA)-CN@BTA (PCNB) nanocomposite. The design integrates smart inhibitor release, photogenerated charge separation and photothermally triggered dynamic covalent bond self-healing within a single system.
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Long-term corrosion protection and photothermal self-healing
Electrochemical impedance measurements showed that the PCNB/EP coating maintained impedance values in the order of 10⁹ Ω·cm² even after 30 days of immersion in a 3.5 wt.-% NaCl solution, demonstrating strong long-term anticorrosive performance. In parallel, the coating exhibited efficient photothermal self-healing behaviour, with substantial scratch closure achieved within 5 h of light irradiation. This performance clearly surpassed that of thermally induced healing alone.
The authors attribute the enhanced performance to the synergistic interplay of several mechanisms: the physical barrier effect of the mesoporous structure, the on-demand release of BTA at defect sites, photogenerated electron transfer from CN and photothermal conversion combined with dynamic disulfide bond exchange within the P(DA-CA) shell. The findings suggest a viable route towards multifunctional epoxy coatings that combine durable corrosion protection with responsive repair capabilities, of potential relevance for the protection of copper and other metal substrates in demanding service environments.
Source: Zhao, C. & Huang, H., Engineering mesoporous graphitic carbon nitride@poly(dopamine-cystamine) with benzotriazole impregnation: A dual-action strategy for high-performance anti-corrosion and intelligent self-healing coatings. Progress in Organic Coatings (2026). https://doi.org/10.1016/j.porgcoat.2026.110246
