A Tough, Room‐Temperature Curable and Economical Structural Adhesive Inspired by Luminescent Squid Skin

ABSTRACT

Structural adhesives play a crucial role in achieving robust and intelligent bonding across diverse scenarios. However, the multi‐scenario bonding reliability and functionality of traditional epoxy adhesives remain constrained by their inherent brittleness, stress sensitivity, and lack of damage sensing capabilities. Inspired by the hierarchical “rigid support–flexible buffer–signal transmission” architecture of luminescent squid skin, a multifunctional structural adhesive fabricated via a scalable one‐pot ring‐opening aminolysis strategy is developed. Rigid epoxy domains mimic the squid collagen fibers to deliver cohesive strength and load‐bearing capacity, while flexible polyurethane/polyurea chains emulate the reflexin protein peptide chain, forming dense hydrogen‐bond networks that dissipate stress and enhance toughness. Aggregation‐induced emission (AIE) fluorophores replicate the mechanism of bioluminescent organelles, enabling in situ visualization and real‐time monitoring of defects. Compared with neat epoxy adhesive, the resulting adhesive exhibits 633.30% increase in toughness, while achieving an outstanding adhesive strength of 13.84 MPa. Adhesive line maintained significant fluorescence performance after seven days of water immersion. Optimized formulation lowers the cost to 25%–50% of commercial polyurethane systems. This bioinspired “rigid–soft–signal” molecular strategy unifies strength, toughness, and self‐sensing capability, offering a sustainable and intelligent adhesive platform for next generation green engineering.