Fully Recyclable Liquid Metal‐Based Ultra‐Stretchable Electronics Enabled by Water‐Modulation‐Degradation‐Reconstruction Polymer‐Gel.

The rapid development of stretchable electronics made by circuits, microchips, and encapsulation elastomers has caused the production of a large amount of electronic waste (e‐waste). The degradation of elastomers can highly minimize the negative effects of e‐wastes. However, chemicals that included acid, alkali, and organics were repeatedly used during the recycling process, which were environmentally unfriendly. Here, a water‐modulation‐degradation‐reconstruction (WDR) polyvinylpyrrolidone (PVP)‐honey composite (PHC) polymer‐gel was developed and could be regarded as encapsulation elastomers to realize a fully recyclable water‐degradable stretchable (WS) electronics with multi‐functions. The stretchability of the PHC polymer‐gel could be modulated by the change of its water retention. The Chip‐integrated liquid metal (LM) circuits encapsulated with the modulated PHC encapsulation elastomer could withstand a strain value of ~3000%. Moreover, we developed a WS biomedical sensor composed of PHC encapsulation elastomer, LM circuits, and microchips, which could be fully recycled by biodegrading it in water to reconstruct a new one. As before, the reconstructed WS biomedical sensor could still simultaneously realize the combination of ultra‐stretchability, recycling, self‐healing, self‐adhesive, and self‐conformal abilities. The results revealed that this study exercises a profound influence on the rational design of multi‐functional WS electronics. [ABSTRACT FROM AUTHOR]