317: Dual-wavelength responsive hydrogel glue with visible-light bonding and uv-triggered debonding via ortho-nitrobenzyl cleavage

Abstract: Removable adhesives with controllable bonding and debonding capabilities are essential for biomedical devices, temporary fixation, and recyclable materials. Here, we present a dual-wavelength hydrogel glue that integrates visible-light polymerization for adhesion and UV-induced degradation for rapid debonding. The system leverages camphorquinone as a visible-light photoinitiator and ortho-notrobenzyl poly(ethylene glycol) dimethacrylate as a UV-cleavable crosslinker, ensuring independent control over adhesion and detachment with orthogonal polymerization and degradation. The degradation rate of the crosslinker increases proportionally with light intensity, providing precise control over cleavage kinetics. The hydrogel glue undergoes a fourfold reduction in adhesion strength within 90 s of 365 nm irradiation, enabling efficient removal. Rheological analysis confirms a significant decrease in storage modulus and crosslinking density after UV exposure, leading to network softening and structural failure. This work pioneers a phototunable hydrogel glue that bridges photopolymerization and photodegradation, offering a promising platform for next-generation adhesives with precise spatiotemporal control and with easy application, good bonding, and rapid UV-triggered debonding.