Transparent, self-recoverable, highly tough, puncture and tear resistant polyurethane supramolecular elastomer with fast self-healing capacity via “hard–soft” hard domain design

Abstract

The integration of superior mechanical properties and fast healing efficiency for self-healing polyurethane supramolecular elastomers is challenging due to the confliction between high chain mobility for healing and high chain rigidity for mechanical properties. Herein, a strategy to design a “hard–soft” hard domain by the cooperation of quadruple hydrogen bonds (HBs) in the mainchain as restriction units and single HBs in the side chain as diffusion units is reported. The resulting transparent supramolecular elastomer exhibited fast self-recoverability, good puncture resistance and superior mechanical properties with a tensile strength of 20.5 MPa, an extensibility of 2043.7%, a toughness of 146.1 MJ m⁻³ and a tear resistance of 13.8 kJ m⁻². Moreover, the fast self-healing capacity (healing efficiency > 82% within 3 h under moderate condition) was realized due to the soft effects of weak HBs in the side chain on the strong HBs in the mainchain. Taking advantage of the merits of the supramolecular elastomer, a flexible sensor was simply fabricated, which showed good self-repairable and stable sensing properties. Thus, the elastomer has great potential in the field of flexible electronics and wearable devices.