Flexible Conductive Supramolecular Polyurethane Elastomer Composites With High Mechanical Strength

ABSTRACT Flexible conductive supramolecular polyurethane elastomer composite with high strength was fabricated via the in situ formation of silver nanoparticles (AgNPs) in the surface layer of supramolecular polyurethane elastomer (SPUE) when soaked in silver salt solution. The as‐prepared SPUE/AgNPs composites possessed high tensile strengths of 63–76 MPa, elongations at break of 783%–879%, toughnesses of 230–374 MJ m ⁻³ , and Young's moduli of 7.9–14 MPa. Owing to the compact AgNP layer, SPUE/AgNPs composites had high electrical conductivities of 0.3–3.7 S cm ⁻¹ . When SPUE/AgNPs composites were stretched to a strain of 0.5%, they could show short response time (80–82 ms) and recovery time (140–180 ms). SPUE/AgNPs composites could display stable relative resistance change (Δ R / R ₀ ) values and high strain sensitivities over a wide range of tensile strains (0.05%–200%). Due to the abundant hydrogen bonds, the damaged SPUE/AgNPs composite could be healed under heat treatment condition, and the healed composite could show stable Δ R / R ₀ similar to that of the fresh SPUE/AgNPs composite. Additionally, SPUE/AgNPs composites had good shape memory performances and solvent‐resistances. The as‐prepared SPUE/AgNPs composites could be used as flexible strain sensors and control switches.