Printable E‐Skin by Direct Ink Writing From Recyclable Hydrogel

ABSTRACT The ability to simultaneously encode programmable architecture and nonlinear mechanical reinforcement into a soft material is pivotal for advancing intelligent 3D‐structured e‐skins capable of robust and adaptive sensing. Herein, we report a recyclable nanocomposite hydrogel that integrates exceptional direct ink writing (DIW) printability, thermal reprocessability, and skin‐like strain‐stiffening behavior. This hydrogel is constructed by embedding PEG‐ b ‐P n BA nanoparticles into a PVA/glycerol matrix, forming a hierarchical dynamic cross‐linking network. The densely strong hydrogen bonds around the nanoparticles provide mechanical reinforcement and directional stress transduction, while the weaker, reversible hydrogen bonds between PEG‐ b ‐P n BA nanoparticles and PVA in the matrix enable efficient energy dissipation and structural reconfigurability. Owing to this hierarchical design, the hydrogel exhibits high mechanical strength, fully recyclability, and stable sensing performance across a wide detection range. Leveraging its thermoplastic and printable properties, we fabricated a pixelated sensor array capable of real‐time recognition of both the direction (GF x = 0.77 vs. GF Y = 0.04) and location of external stimulis. Furthermore, a fully soft, miniaturized flexible keyboard prototype was developed, demonstrating high‐resolution tactile sensing and intelligent signal decoding. These features position the hydrogel as a promising platform for next‐generation flexible electronics, including electronic skins, neuromorphic sensing systems, and adaptive soft robotics.