Room-temperature self-healing supramolecular polyurethanes based on the synergistic strengthening of biomimetic hierarchical hydrogen-bonding interactions and coordination bonds

Developing a new generation of polymeric materials that integrate robust mechanical properties with ultra-high self-healing efficiency at ambient temperature remains a formidable challenge due to the proverbial trade-offs among strength, toughness, and self-healing ability. Herein, inspired by biological systems (titin protein molecular structure and Nereis jaws), a series of updated supramolecular polyurethanes have been successfully synthesized by incorporating hierarchical hydrogen-bonding motifs into the polymer matrix and subsequently coordinated with Zn(2+ )ions. Relying on collaborative reinforcement of optimized hierarchical hydrogen bonds and metal-ligand coordination bonds, the resulted supramolecular elastomers exhibited a robust strength of -14.15 MPa, an excellent toughness of-47.57 MJ m(-3), and Young's modulus of -146.92 MPa. Benefiting from the rational design of hard domains, high mobility of chains, and the synergistic effect of multiple non-covalent interactions, the mechanical properties are far superior to the previously reported room-temperature self-healing materials. In addition, with the structural design of "inner soft and external hard " model, we also fabricated a bilayer polymer film with a gradient distribution that can achieve rapid self-healing, with an unexpectedly high self-healing efficiency of 95% at ambient temperature in 24 h. This work opens up a new avenue for fabricating room-temperature self-healing materials with robust mechanical strength and toughness at the same time.