Room-temperature self-healing and recyclable polyurethane elastomers with high strength and superior robustness based on dynamic double-crosslinked structure

Mechanically robust elastomers with the functionalities of room-temperature self-healing ability and even recyclability provide new opportunities to revolutionize next-generation flexible electronics. However, it remains a great challenge to synthesize such materials due to the conflicting requirements of the self-healing ability and mechanical robustness for the dynamicity of crosslinks. Herein, a room-temperature self-healing and recyclable polyurethane (PU) elastomer with ultrahigh mechanical performance is constructed by synergistically incorporating dynamic disulfide bonds and multiple hydrogen bonds (H-bonds) into a PU chain. The introduction of diazolidinyl urea (DU) motifs forms strong H-bonds and branching crosslinking points, improving the robustness of the crosslinked structure, and the fast metathesis of the aromatic disulfide bonds mainly contributes to the dynamicity of the crosslinked network. The resulting PU elastomers exhibit high tensile strength (14.08 MPa), toughness (64.6 MJ m−3), superior elastic restorability, outstanding self-healing capability (∼81% at room temperature), and multiple recyclability. Furthermore, a wearable sensor based on this elastomer is constructed to monitor different human motions, demonstrating the potential application in wearable electronics.