Self-healing conductive hydrogels based on alginate, gelatin and polypyrrole serve as a repairable circuit and a mechanical sensor

Conductive materials including graphene, metal and conjugated polymers, combined with self-healing hydrogels are attracting increasing attention in biosensors and bioelectrodes. In this work, we propose one self-healing conductive hydrogel with good morphology and performance based on an alginate-gelatin network and polypyrrole (Ppy) via low-temperature fabrication. The alginate/gelatin network consists of extensive reversible Schiff base units that can act as dynamic crosslinking agents to self-heal the hydrogel. Ppy as one conductive polymer provides the hydrogel with conductivity and good mechanical properties. To demonstrate the applications, we insert the hydrogel into a disconnected circuit to repair or act as one component to light up bulbs. In addition, the conductive hydrogel possesses mechanical responses towards bending or compression, thus it can monitor hand movements and paves the way to a flexible, mechanical sensor. This work proposes a facile method to fabricate one novel self-healing conductive hydrogel and demonstrates its applications in repairable circuits and mechanical sensors that may have potential prospects in circuit repair materials, biocompatible/medical devices, and flexible sensors.