Supramolecular and Physically Double-Cross-Linked Network Strategy toward Strong and Tough Elastic Fibers.

The strength and toughness are two trade-off properties of a material, yet Nature can achieve strong and tough materials by introducing sacrificial bonds into a system. Here, we present a four-component multiblock copolymer (mBCP) approach toward strong and tough elastic fibers, by introducing terpyridine moieties into poly(ether ester) mBCP elastomers. After coordination with Fe(II), supramolecular cross-links are formed within the physically cross-linked thermoplastic elastomers. The toughening elastic fibers with a double-cross-linked network structure show high tensile strength (ca. 300 MPa) and toughness (ca. 100 MJ m -3 ). In addition, they display excellent resilience with enhanced self-healing properties. Our strategy provides a promising way for the development of strong and tough elastomers by introducing metal-ligand sacrificial bonds into mBCPs elastomers.