Fast photothermal poly(NIPAM-co-β-cyclodextrin) supramolecular hydrogel with self-healing through host–guest interaction for intelligent light-controlled switches

Abstract

A graphene oxide/poly(N-isopropylacrylamide-co-β-cyclodextrin) (GO/poly(NIPAM-co-β-CD)) hydrogel has been synthesized through host–guest interaction between β-cyclodextrin (β-CD) and the isopropyl group of N-isopropylacrylamide (NIPAM). The product exhibits rapid responses to the stimuli of temperature and near-infrared (NIR) irradiation, self-healing properties, and excellent mechanical properties. The host–guest interaction serves as the main physical cross-linker, while a hydrogen bond between the hydroxyl group of β-CD, GO sheets and amide group of NIPAM acts as a secondary cross-linker. The volume phase transition temperature and NIR response rate of such a hydrogel are controlled by its contents of β-CD and GO. The obtained hydrogels showing excellent properties might be applied in remote contactless control devices in advanced smart technologies. Based on the excellent characteristics of the hydrogels, remote light-controlled switches have been designed, and more applications will be explored, such as intelligent light-controlled drivers and soft robots.