Towards Dynamic but Supertough Healable Polymers through Biomimetic Hierarchical Hydrogen‐Bonding Interactions

A biomimetic (titin protein molecular structure) strategy is reported for preparing transparent and healable elastomers featuring supertoughness (345 MJ m−3) and high tensile strength (44 MPa) after self‐healing enabled by hierarchical (single, double, and quadruple) hydrogen‐bonding moieties in the polymer backbone. The rigid domain containing hierarchical H‐bonds formed with urethane, urea, and 2‐ureido‐4[1H]‐pyrimidinone groups leads to a durable network structure that has enhanced mechanical properties and is also dynamic for rapid self‐healing. Healable polymers with hierarchical hydrogen‐bonding interactions show excellent recoverability and high energy dissipation owing to the durable interaction between polymer chains. This biomimetic strategy of using hierarchical hydrogen bonds as building blocks is an alternative approach for obtaining dynamic, strong, yet smart self‐healing polymers for heavy‐duty protection materials and wearable electronics. Supertough self‐healing elastomers were constructed by a biomimetic synthetic strategy and control of the nanophase structure with hierarchical (single, double, quadruple) hydrogen‐bonding motifs. The successive dynamic interaction of the H‐bonds and increased chain mobility contribute to the self‐healing and supertough mechanical properties. The toughness after self‐healing reached 345 MJ m−3.