Tough Elastomers with Superior Self‐Recoverability Induced by Bioinspired Multiphase Design

Incorporating reversible sacrificial bonds in network polymers not only toughens these materials but also endows them with self‐recoverability. However, self‐recoverability is only realized for dispersed energy less than 10 MJ m −3 . It remains a challenge to achieve simultaneous high stretchability, toughness, and recoverability. Here, inspired by the structure of mussel byssus cuticles, a new design strategy is proposed and demonstrated to improve both the toughness and self‐recoverability of elastomers by introducing a microphase‐separated structure with different physical crosslink densities. This structure can be achieved using a carefully designed comonomer sequence distribution of hydrogen bonding units in an ABA‐type triblock copolymer. The A blocks form hard domains with dense crosslinking that prevents macroscopic deformation, while the B blocks form a softer matrix with sparse and dynamic crosslinks that serve as sacrificial bonds. This elastomer exhibits high toughness (≈62 MJ m −3 ), self‐healing, and most notably, excellent self‐recovery (recovery against 650% elongation and 17 MPa tensile stress with a dissipated energy >27 MJ m −3 at room temperature). This combination of toughness, self‐healing, and self‐recovery expands the range of applications of these advanced dynamic materials.