Facile Preparation of Highly Stretchable and Recovery Peptide-Polyurethane/Ureas.

In this work, a new class of highly stretchable peptide-polyurethane/ureas (PUUs) were synthesized containing short -sheet forming peptide blocks of poly(-benzyl-l-glutamate)--poly(propylene glycol)--poly(-benzyl-l-glutamate) (PBLG--PPG--PBLG), isophorone diisocyanate as the hard segment, and polytetramethylene ether glycol as the soft phase. PBLG--PPG--PBLG with short peptide segment length (<10 residues) was synthesized by amine-initiated ring opening polymerization of -benzyl-l-glutamate--carboxyanhydrides (BLG-NCA), which shows mixed α-helix and -sheet conformation, where the percent of -sheet structure was above 48%. Morphological studies indicate that the obtained PUUs show -sheet crystal and nanofibrous structure. Mechanical tests reveal the PUUs display medium tensile strength (0.25⁻4.6 MPa), high stretchability (>1600%), human-tissue-compatible Young's modulus (226⁻513 KPa). Furthermore, the shape recovery ratio could reach above 85% during successive cycles at high strain (500%). In this study, we report a facile synthetic method to obtain highly stretchable and recovery peptide-polyurethane/urea materials, which will have various potential applications such as wearable and implantable electronics, and biomedical devices.