Seeking Answers from Tradition: Facile Preparation of Durable Adhesive Hydrogel Using Natural Quercetin

Adhesive hydrogels containing catechol moieties have many important applications, but the fabrication of effective long-lasting adhesive hydrogels remains a challenge because of oxidative damage. Inspired by the traditional use of quercetin in ancient China, here, we have developed a novel method, based on quercetin-assisted photoradical chemistry, to fabricate a durable adhesive hydrogel, Q-hydrogel. In the presence of light, quercetin generates quinone/semiquinone radicals, which subsequently interact with ammonium persulfate (APS) to produce a large amount of free radicals and initiate polymerization of the hydrogel. As-prepared Q-hydrogel showed good mechanical and adhesive properties, which were attributed to the inherent structural advantages of quercetin. Because of the resistance of quercetin to oxidation, as-prepared Q-hydrogel also showed good adhesive properties even after treatment with oxidizing agents. Capitalizing on its conductivity and adhesive properties, Q-hydrogel was successfully used to produce wearable sensors capable of detecting human motion.