Healable and Recyclable Elastomers with Record‐High Mechanical Robustness, Unprecedented Crack Tolerance, and Superhigh Elastic Restorability

TLDR

Spider silk is a highly robust natural material with exceptional strength, toughness, and elasticity. The study develops a healable, recyclable supramolecular elastomer that surpasses spider silk in true stress at break and toughness. The elastomer’s strength derives from engineered hydrogen‑bond arrays formed by acylsemicarbazide and urethane segments linked with flexible spacers, acting as reversible crosslinks and sacrificial bonds. The elastomer records the highest tensile strength for polymeric elastomers, shows superior crack tolerance with fracture energy exceeding metals, and restores dimensions after elongation over 12×.

Abstract

Abstract Spider silk is one of the most robust natural materials, which has extremely high strength in combination with great toughness and good elasticity. Inspired by spider silk but beyond it, a healable and recyclable supramolecular elastomer, possessing superhigh true stress at break (1.21 GPa) and ultrahigh toughness (390.2 MJ m −3 ), which are, respectively, comparable to and ≈2.4 times higher than those of typical spider silk, is developed. The elastomer has the highest tensile strength (ultimate engineering stress, 75.6 MPa) ever recorded for polymeric elastomers, rendering it the strongest and toughest healable elastomer thus far. The hyper‐robust elastomer exhibits superb crack tolerance with unprecedentedly high fracture energy (215.2 kJ m −2 ) that even exceeds that of metals and alloys, and superhigh elastic restorability allowing dimensional recovery from elongation over 12 times. These extraordinary mechanical performances mainly originate from the meticulously engineered hydrogen‐bonding segments, consisting of multiple acylsemicarbazide and urethane moieties linked with flexible alicyclic hexatomic spacers. Such hydrogen‐bonding segments, incorporated between extensible polymer chains, aggregate to form geometrically confined hydrogen‐bond arrays resembling those in spider silk. The hydrogen‐bond arrays act as firm but reversible crosslinks and sacrificial bonds for enormous energy dissipation, conferring exceptional mechanical robustness, healability, and recyclability on the elastomer.