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)-b-poly(propylene glycol)-b-poly(-benzyl-l-glutamate) (PBLG-b-PPG-b-PBLG), isophorone diisocyanate as the hard segment, and polytetramethylene ether glycol as the soft phase. PBLG-b-PPG-b-PBLG with short peptide segment length (<10 residues) was synthesized by amine-initiated ring opening polymerization of -benzyl-l-glutamate-N-carboxyanhydrides (BLG-NCA), which shows mixed -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.