Liquid metal complexing Fe₃O₄ nanoparticles enable rapid polymerization of magnetically conductive hydrogels for various flexible electronics

Hydrogels have recently emerged as promising materials for the next-generation of bioelectronic, due to their similarities to biological tissues, versatility in electrical, mechanical, and bio-functional engineering. This study discoveries that the free radicals produced by co-sonication of Fe₃O₄ nanoparticles (Fe₃O₄ NPs) and liquid metal (LM) in aqueous solution can initiate the polymerization of acrylamide to prepare hydrogels. A suspension of LM- Fe₃O₄ was created and successfully initiated fast polymerization (< 2 min) of acrylamide to form a robust hydrogel with superior conductive properties. The hydrogel has all-encompassing adhesive properties, is highly injectable, and possesses magnetic actuation capabilities. Utilizing the conductive and magnetic properties of hydrogels, a dual control sensor for Morse code transmission was created. Employing the in-situ polymerization properties, a series of flexible electronic devices have been fabricated with hydrogel, including plant leaf electrodes, injectable plant electronic devices and zinc ion batteries. This work presents an unconventional strategy for integrating plants with electronics on the platform of hydrogels, which provides current research ideas in the fields of plant electrophysiology and wearable electronics.