Biomineralization-Inspired Ultra-tough and Robust Self-healing Waterborne Polyurethane Elastomers

Creating materials that exhibit properties analogous to biological muscles, such as toughness, strength, elasticity, and self-healing capabilities, presents a significant challenge. Here, inspired by the biomineralization process in which macromolecules regulate mineral crystal assembly, we propose a strategy to induce in situ crystallization and assembly of minerals using ice-controlled media. This approach enables the fabrication of waterborne polyurethane (WPU) elastomers with exceptional mechanical performance (including an unprecedented toughness of approximately 1.9 GJ m^–3, remarkably high fracture stress of around 65 MPa, and extraordinary elongation at break reaching 6215%), as well as rapid self-healing capability (with matrix recovery and mineral reconstruction occurring within only 4 min). During the crystallization and assembly of minerals, the steric hindrance provided by WPU and tannic acid (TA) effectively regulates mineral crystal growth, while the cross-linking interaction between WPU and TA facilitates the in situ assembly of inorganic mineral nanocrystals into flower-like architectures. This synergistic process ultimately results in the formation of an organic–inorganic embedded structure within the WPU matrix. Moreover, this unique structural design establishes a novel theoretical framework for understanding the stress dissipation mechanisms of WPU elastomers under external forces. In summary, this work presents an innovative strategy for fabricating WPU elastomers with high mechanical performance and offers in-depth insights into the structural principles that underpin their exceptional mechanical performance.