Fully biofriendly, biodegradable and recyclable hydrogels based on covalent-like hydrogen bond engineering towards multimodal transient electronics

Biodegradable or recyclable transient electronics originated from natural polymers are considered as significant solution for electronic waste (e-waste) management, sustainable development, and emerging implantable de-vices. Yet, they are mostly struggling from mismatched mechanical features with human tissue and inferior environmental adaptability. In this work, based on the novel covalent-like hydrogen bond engineering, we developed a syrup-modified gelatin/Ag-hydrogel, which is entirely derived from natural or safe constituents and highly stretchable, yet fully biodegrades or recyclable. Meanwhile, strong covalent-like hydrogen bonds endow it with several favorable features of adhesion, rapid self-healing and antifreeze. A series of multi-modal application scenarios are further demonstrated to verify the adaptability of this platform that integrates various attributes. Overall, this work provides the feasibility of modified natural polymers to replace synthetic polymers, and provides a general toolbox for the construction of functional units for "green electronics" and the expansion of application models.