The biomimetic design provides efficient self-healing of ultrahigh-tough and damage-warning bio-based elastomer for protective clothing of metals

Facing the ubiquitous corrosion threat, the great significance of developing high-performance protective materials with the dual function of self-healing defects and self-warning damage is extremely challenging. Herein, inspired by the biological skin and pearls, we proposed that the biological polyurethanes (PU) embedded with multiple dynamic bonds (reversible hydrogen bonds and aromatic disulfide bonds) were combined with polydopamine (PDA)/1,10-phenanthroline (Phen)/graphene oxide (GO) (PPG) nanosheets (PDA encapsulated GO with Phen) to obtain a versatile nacre structure polymer with the interface hydrogen bond between PPG and PU matrix. The biomimetic polymer not only guarantees ultrahigh toughness (116.1 MJ·m⁻³) and abnormal elongation (2320%) but shows satisfactory repair performance (81% under 25 °C for 3 h), and the coating can accelerate damage recovery (87%) under near-infrared light (NIR) irradiation for 1 h due to the photothermal properties of PPG. The warning of damages in the coating can be enabled through the Phen chelation Fe²⁺ ions that bring in the corrosion reaction to produce a conspicuous red color, thereby achieving the active warning function of the bionic coating on defects for the first time. In addition, the electrochemical tests exhibit that the repair performance and protection effect of the biomimetic coating in 3.5 wt.% NaCl solution are also trustworthy, and this highly reliable bio-based bionic coating brings a revolutionary program to inaugurate multifunctional and high-performance intelligent materials under harsh environments.