A Conductive Self‐Healing Double Network Hydrogel with Toughness and Force Sensitivity

Abstract Mechanically tough and electrically conductive self‐healing hydrogels may have broad applications in wearable electronics, health‐monitoring systems, and smart robotics in the following years. Herein, a new design strategy is proposed to synthesize a dual physical cross‐linked polyethylene glycol/poly(acrylic acid) (PEG/PAA) double network hydrogel, consisting of ferric ion cross‐linked linear chain extensions of PEG (2,6‐pyridinedicarbonyl moieties incorporated into the PEG backbone, PEG‐H2pdca) as the first physical network and a PAA‐Fe3+ gel as the second physical network. Metal‐ion coordination and the double network structure enable the double network hydrogel to withstand up to 0.4 MPa tensile stress and 1560 % elongation at breakage; the healing efficiency reaches 96.8 % in 12 h. In addition, due to dynamic ion transfer in the network, the resulting hydrogels exhibit controllable conductivity (0.0026–0.0061 S cm−1) and stretching sensitivity. These functional self‐healing hydrogels have potential applications in electronic skin. It is envisioned that this strategy can also be employed to prepare other high‐performance, multifunctional polymers.