Carbon nitride initiated photopolymerization into a luminescent elastomer hydrogel

Abstract

Functionalized elastomer hydrogels with tough and stretchable mechanics are desired soft materials extensively investigated for various field applications from soft electronics to sensors. Herein, we rationally designed a luminescent elastomer hydrogel by combining the functional carbon nitride (CN) unit cross-linkers with hydrophilic polymer chains into three-dimensional (3D) networks. The aqueous exfoliated and dispersed CN initiated the photopolymerization and gelation of an acrylamide (AM) monomer into a polyacrylamide (PAM)-CN elastomer hydrogel (PAM-CN ESH) under Xe light irradiation, without any conventional initiators and cross-linkers. Moreover, the mechanical attributes of toughness, stretchability and shape recovery for the PAM-CN ESH can be modulated by swelling in ethanol and water to form uniform and dense interlinked channels. Besides, the optical transparent PAM-CN ESH presents enhanced stable blue fluorescence emission around 430 nm, and accurately recognizes and detects Al³⁺ in an aqueous solution with a limit of detection (LOD) of 0.26 μM.