Adhesive, self-healing polydopamine/reduced graphene oxide composite hydrogel for self-powered application

Graphene-based hydrogels have a broad application prospect in various fields due to their excellent adsorption, electrical conductivity, water retention, flexibility, etc. In this work, polydopamine/reduced graphene oxide (PDA/rGO) composite hydrogel was prepared using water bath heating. The prepared PDA/rGO hydrogel has high swelling ratio, good adhesiveness, and self-healing ability. Furthermore, the generation of electric current was observed when pressure was applied to the PDA/rGO hydrogel filled with NaCl solution, indicating the self-powered property of the hydrogel. The PDA/rGO hydrogel is self-powered because the negative groups on the hydrogel matrix attract cations from the NaCl solution, leaving mobile negative ions in the solution. The pressure-induced flow of liquid in the hydrogel' s nanochannels drives the migration of mobile ions through the channels, generating a net ionic flow. These properties of PDA/rGO hydrogel suggest that the material would be promising for power sources of wearable devices by harvesting ambient mechanical energy.