Mechanically Robust and Self‐Healing Polyurethane Elastomer Based on Hierarchical Hydrogen Bonds

Abstract It is a formidable challenge to fabricate mechanically robust and self‐healing polymeric materials. In this work, a facile but effective approach based on constructing hierarchical hydrogen bonds (H‐bonds) is used to combine high mechanical robustness and healing efficiency into one artificial polyurethane (PU) elastomer. The infrared spectrum and molecular simulations demonstrate the formation of hierarchical H‐bonds, which are assembled by the strong and weak H‐bonds. The hierarchical H‐bonds appear to have two advantages. On the one hand, the hierarchical breaking of the strong and weak H‐bonds can effectively strengthen and toughen the PU elastomer. The strong H‐bonds maintain the integrity of the PU network, while the weak H‐bonds dissipate considerable energy during stretching; on the other hand, the rapid dissociation and organization of hierarchical H‐bonds provides the driving force for the healing process. Thus, the hierarchical H‐bonds efficiently solve the inherent contradiction between mechanical strength and healing dynamics. As a result, the PU elastomer exhibits excellent mechanical properties (32.5 MPa of tensile strength and 84.1 MJ m −3 of toughness). Meanwhile, this PU elastomer shows high healing efficiency (91.4%) and also exhibits 100% scratch recovery. This design strategy may provide a simple yet effective way to produce robust self‐healing polymeric materials.