Bioinspired mechanically tough, high Adhesion, and healable polyurethane coating for high-temperature anti-corrosion and anti-cavitation applications

High-temperature corrosion in marine environments demands advanced protective coatings. Inspired by spider silks and mussels, a mechanically tough, high adhesion and healable polyurethane composite coating (PU-FM) was developed. Specifically, a chain extender (FA-FGE diol) rich in multiple Diels-Alder (DA) furan rings was developed to determine the optimal PU matrix, combined with 1 wt% dopamine-modified multi-walled carbon nanotubes. The abundant DA bonds not only provide thermal stability and compactness of the polymer chain for high-temperature anti-corrosion, but also support the compatibility of self-healing properties. PU-FM exhibited outstanding mechanical properties, with a high toughness of 356MJ·m −3 , strength of 72 MPa, and adhesion of 16.2 MPa. After 60 h of cavitation, average corrosion depths of PU-FM were only 3.4 nm (20℃) and 8.4n m (80℃). The |Z| 0.01Hz values of PU-FM maintained 1.111 × 10 9 Ω·cm 2 (20℃) and 7.361 × 10 7 Ω·cm 2 (80℃) after exposed to 3.5 wt% NaCl solutions for 30 d. Moreover, PU-FM also demonstrated 93 % self-healing efficiency under near-infrared light for 90 s, retaining 81 % after three cycles. This approach, combining DA bond-rich chain extenders with nanofiller reinforcement, offers a novel solution for high-temperature anti-corrosion and self-healing coatings, addressing critical challenges in marine and industrial applications.