Mechanical characterization of spider silk inspired peptide-containing hybrids

Spiders can produce different types of silks with different functions by tuning the hierarchical structure of spidroin. Inspired by the secondary structure of spider silk, a series of peptide-polyurethane/urea (PUU) hybrids with various peptide contents were synthesized in this work. By effective control of polymerization degree, simultaneous presence of α-helixes and β-sheets in the polymer was realized. The modulus of films increased with peptide loading and reached more than 200 MPa at 71.1% peptide content. Notably, the PUU hybrid with 41.5% peptide content (P-41.5) showed the highest tensile strength (6.6 MPa) and strain (1238%). At the same time, this film (P-41.5) exhibited shape memory effect at 37 °C, as well as excellent shape recovery ratio during successive cycles at 100% strain. Furthermore, Ag nanowires/P-41.5 hybrid film exhibited superb electric resistance stability under bending and stretching conditions, making it a promising material for strain sensors.