Super tough, ultra-stretchable, and fast recoverable double network hydrogels physically crosslinked by triple non-covalent interactions

Incorporating sacrificial bonds into hydrogels networks has been demonstrated an efficient way to obtain ultrahigh strength , but is usually at the expense of flexibility and recoverability. This study demonstrates novel triple physically crosslinked hydrogels with very high stretchability, toughness and rapid self-recovery at ambient conditions. Physically crosslinked κ-carrageenan acts as the first network to host free radical copolymerization of polymers with Pluronic F127 diacrylate micelles . Hydrophobic association of micelles in the second network contributes to outstanding stretchability (over 1100%) and toughness (10.83 MJ/m 3 ). Further crosslinking of the second network through tridentate Fe 3+ –COO − coordination significantly enhances the fracture strength up to 2.7 MPa, and elastic modulus 1171 kPa. Systematic investigations demonstrate the key roles played by non-covalent crosslinking on energy dissipation during loadings and the damaged non-covalent networks could recover 40% toughness in 1 min at ambient conditions. These hydrogels are promising for applications as biocompatible load-bearing materials.