Closed-Loop Recyclable, Tough, and Solvent-Resistant Electromagnetic Shielding Hydrogel Inspired by Dragonfly

Electromagnetic shielding hydrogels have attracted much attention in stress sensing, motion monitoring, and bioelectronics. However, existing works mainly focus on improving electromagnetic shielding and sensing performance while ignoring the development of solvent resistance and material closed-loop recycling performance required for liquid-environment applications. In this work, a dragonfly-inspired solvent-resistant and closed-loop recyclable electromagnetic shielding hydrogel is successfully prepared via the biomimetic dual-network structure constructed by combining rigid polyimide (PI) with flexible poly(vinyl alcohol) (PVA). The electromagnetic shielding hydrogel features high mechanical strength and reprocessing and welding capabilities. More importantly, the hydrogels demonstrate closed-loop recycling of polyimide monomers and graphene nanofillers, and the recycled monomers and graphene can be reused in the construction of solvent-resistant electromagnetic-shielding hydrogels. Furthermore, electromagnetic shielding hydrogels are designed as stress sensors for monitoring strain and pressure signals, whether in air, water, or organic solvents. It is anticipated that the strategy of solvent-resistant and sustainable electromagnetic shielding hydrogels will provide a promising opportunity for various flexible electronics in liquid environments.