Light-Triggered Volumetric Shrinkage Enables Ambient-Condition Debonding in Nanocomposite Adhesives

End-of-life product recycling is often impeded by permanent adhesives that hinder disassembly. While stimuli-responsive adhesives offer controlled debonding, most rely on thermal or chemical triggers that are energy-intensive or environmentally harmful. Here, we report a light-responsive nanocomposite adhesive that enables ambient-condition debonding triggered by NIR irradiation. The system consists of a thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) matrix embedded with a UV-curable cross-linker and polydopamine nanoparticles loaded with a near-infrared (NIR) absorbing dye. Upon NIR irradiation (808 nm, 1 W/cm², 60 s), localized photothermal heating drives a phase transition in PNIPAM, triggering macroscopic shrinkage of the adhesive layer. This results in a reduction of adhesive thickness, interfacial contact loss, and a drop in adhesion strength, yielding a residual strength that is low enough for facile mechanical separation and enabling clean and residue-free release. The adhesive also demonstrates rapid UV-curing (365 nm, 10 s) and strong initial bonding (∼0.5 MPa on PET) for a nonstructural adhesive. This dual-wavelength photothermal adhesive system enables controlled disassembly of bonded components at the end-of-life stage, offering a practical pathway toward sustainable product separation and subsequent material recovery.