Synergistic Enhancement of Low-Temperature Self-Repairing Polyurethane Elastomers through Quadruple Hydrogen Bonds and Coordination Bonds

The preparation of polyurethane (PU) materials with both low-temperature rapid repair and robust mechanical properties still remains a challenging yet promising endeavor. Herein, a multifunctional linear PU supramolecular elastomer was successfully synthesized, incorporating multiple hydrogen bonds and coordination bonds to endow it with self-healing properties. The results demonstrated that the self-healing PU exhibited strong tensile strength (∼30 MPa), high elongation at break (∼925%), and excellent toughness (∼112 MJ/m³) through synergistic effect of hydrogen bonds and metal coordination bonds. After 12 h of repair at 45 °C, the repair efficiency of the PU film reaches 87%. The self-repairing PU film also possesses excellent transparency with a transmittance exceeding 90%. Furthermore, the PU film demonstrates good recyclability; even after multiple recycling and reshaping, its mechanical properties do not show a significant decrease. Therefore, the development of self-healing PU with low-temperature capabilities holds significant theoretical implications, practical value, and broad application prospects. These materials are expected to find wide-ranging applications in various fields in the future.