UV-assisted repair of disulfide-based covalent adaptable networks for sustainable protective coatings

Abstract

Dynamic network exchange reactions enable covalent adaptable networks (CANs) to combine the robustness of thermosets with malleability and reprocessability. However, most CANs rely on thermally activated bond exchange, which requires high temperatures and prolonged processing times while heating the entire material and limiting localized repair. Here, we report a CAN incorporating UV- and heat-responsive disulfide bonds that enables topology rearrangement under mild conditions. The network becomes malleable upon heating or, more efficiently, under UV irradiation, allowing for bond exchange without bulk heating. Compared with nonirradiated conditions, UV irradiation at room temperature significantly accelerates creep deformation, enabling practical UV-assisted welding without thermal input. Importantly, UV activation provides spatially localized control, allowing for site-specific repair while leaving surrounding regions unaffected. This selective repair capability is demonstrated through application of the CAN as a repairable anti-corrosion coating. This UV-responsive CAN provides a versatile platform for spatiotemporally controlled processing and repair of network polymers, offering a sustainable pathway to extend material lifetime through localized, low-energy reprocessing. This study presents a heat- and UV-responsive disulfide-based covalent adaptable network (DS-CAN) as a repairable anticorrosion coating under mild conditions. UV irradiation at room temperature activates dynamic disulfide exchange, enabling localized network rearrangement, welding, and patching. The restored coatings recover structural integrity and corrosion resistance, offering an energy-efficient, on-demand, spatiotemporally controlled repair strategy for functional coatings.