Visible Light Induced Ultra‐High Adhesion Enhancement by Carbene O─H and C─H Bonds Insertion

Abstract A novel aryl diazo ester‐based acrylate monomer is synthesized and incorporated into radical copolymerization to develop a visible light‐responsive adhesive. This aryl diazo ester exhibits stability during polymerization but rapidly activates under visible light irradiation, generating carbene intermediates that undergo instantaneous O─H and C─H bonds insertion reactions. This mechanism enables in situ covalent cross‐linking within the adhesive matrix and at the adhesion interface, synergistically enhancing both cohesion and interfacial adhesion. Compared to non‐irradiated counterparts, the bonding strength increased by 157% (reaching 22.1 MPa) upon visible light irradiation. Remarkably, ambient sunlight also triggered this enhancement, highlighting its energy‐efficient and eco‐friendly attributes. This work proposes an innovative strategy for designing stimuli‐responsive smart adhesives with potential applications in ultra‐high‐strength fields such as structural bonding.