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Self-healing water-borne polyurethane coating offers reliable corrosion protection
Researchers have developed an eco-friendly self-healing coating based on waterborne polyurethane. The dual dynamic bond network provides high mechanical strength, efficient self-healing and long-term corrosion resistance.
A Chinese research team has introduced a novel self-healing coating based on waterborne polyurethane (WPU). The aim was to overcome the challenge of combining mechanical strength, self-healing performance and anti-corrosion capacity in one system. To achieve this, the researchers combined reversible disulphide bonds, acylhydrazone bonds and thermo-sensitive hydrogen bonds.
The dual dynamic networks are created through chemical cross-linking of acylhydrazone bonds and physical hydrogen bonding among acylhydrazone, urethane and urea groups. This structure significantly enhances the barrier effect, mechanical robustness and self-healing efficiency of the coating.
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High self-healing efficiency and corrosion resistance
The developed polymer, WPUSS-P4, achieved a yield stress of 14.6 MPa, a tensile strength of 20.9 MPa and a self-healing efficiency of 93 %. In corrosion tests, the coating showed strong and durable protection after 240 hours of EIS testing in 3.5 % NaCl solution and 120 hours of salt spray exposure in 5 % NaCl solution. Notably, intact and self-healed WPUSS-P4 coatings exhibited almost identical characteristics, with nearly 100 % recovery of corrosion resistance.
This research provides a promising strategy for sustainable and environmentally friendly anti-corrosion materials suitable for metallic substrates.
Source: Fu, B. et al., Eco-friendly fabrication of self-healing robust waterborne polyurethane based on dual dynamic networks for metal corrosion protection. Prog. Org. Coat. 203, 109188 (2025).
