Room‐Temperature Healable and Mechanically Robust Polyurea‐Urethane Based on Dynamic Tetrahedral Boronate‐Esters Bonds and Hydrogen Bonds

ABSTRACT Although some studies have reported high‐toughness or high‐strength self‐healing materials, the self‐healing process still requires demanding conditions such as high temperatures. It remains challenging to achieve a balance between mechanical properties and self‐healing efficiency under mild conditions. Herein, we design a novel self‐healing polyurea‐urethane (PUU) material. The polymer has crosslinked internal “cores” and well‐designed flexible chains with multiple alicyclic structures, which are crosslinked via tetrahedral boronate‐esters bonds (TBEs) and hydrogen bonds, resulting in a dynamic crosslinked PUU network (denoted as TBE‐PUU). The resulting materials (TBE‐PUU 2 ) not only exhibit outstanding tensile strength (28.5 MPa), stretchability (1217%), toughness (166.1 MJ m −3 ), etc., but also possess excellent self‐healing ability in response to water or thermal stimuli. It achieves high self‐healing efficiency of 92.0% at room temperature for 48 h with the aid of water and 97.7% at 60°C for only 8 h. The new strategy offers new possibilities to seek a balance between material dynamic properties and mechanical robustness.