Gecko's Toes-Inspired High-Adhesive and Self-Healable Elastomer in Marine Conditions: Humidity-Triggered Crosslinking and Damage Sensing

The development of smart materials capable of underwater self-healing, mechanical robustness and damage-healing sensing attributes holds great promise for applications in marine energy exploitation. However, achieving excellent humidity self-healing, superior adhesion, and effective damage sensing and monitoring properties simultaneously is challenging because the disturbance of water molecules to dynamic-interaction reconstruction. Herein, inspired by gecko's toes, an ultra-robust environmental adaptative self-healing supramolecular elastomer is designed by molecular engineering of water-insensitive dynamic network, which possesses efficient self-healing and visual damage sensing capabilities. Through coupling design of hierarchical hydrogen bonds, humidity-tolerant catechol coordination and photothermal sensitivity moiety, the elastomer achieves high Young's modulus (157.72 MPa) and superior self-healing efficiency (84.68%). Moreover, the autonomous association between catechol groups and steel surface endows the resultant elastomer with outstanding adhesion force (12.82 MPa) in humid conditions. Furthermore, this elastomer can be fabricated as a patch covered on steel substrates. The damage-healing dynamics and interfacial failure characteristics are visually demonstrated by the reversible fracture and reconstruction of iron-catechol coordination bonds, realizing real-time damage sensing and monitoring. This study provides a novel strategy for the design of next-generation smart protective materials in harsh marine environment, and expected for ensuring the stable operation of marine energy mining equipment.