A novel silk-based segmented block copolymer containing GlyAlaGlyAla β-sheets templated by phenoxathiin

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2000-01, Vol.38 (2), p.352-366
• Main Authors: Rathore, Osman, Winningham, Michael J., Sogah, Dotsevi Y.
• Format: Article
• Language: English
• Subjects: alanine; Amino acids; Aminoacid polymers; Applied sciences; bioinspired; Biopolymers; Exact sciences and technology; glycine; Molecular weight; Morphology; Phase interfaces; Phase separation; phenoxathiin; Physicochemistry of polymers; Polyethylene glycols; Polymerization; Polypeptides; Silk; Synthetic biopolymers; template; β-sheets
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/(SICI)1099-0518(20000115)38:2<352::AID-POLA10>3.0.CO;2-P

A novel segmented block copolymer, containing polyethylene glycol segment and GlyAlaGlyAla sequence derived from B. mori silk, has been prepared as a model for silk‐based materials using both solution and interfacial techniques. Inherent viscosity, size exclusion chromatography, and light‐scattering measurements gave molecular weight between Mw 34,000–39,000. Evidence for phase separation was provided by differential scanning calorimetry, which gave two Tg's at −57 °C and 111 °C, and transmission electron microscopy, which showed a morphology in which the peptide domain, estimated to be about 20–50 nm, was dispersed in the continuous polyether phase. Solid‐state FTIR spectroscopic results showed that the polymer contained both parallel and antiparallel β‐sheet stacks, and that the solution‐polymerized material has the higher β‐sheet content. This was further confirmed by 13C NMR, which gave about 80% total β‐sheet content for the solution‐polymerized product and about 40% for the polymer obtained by interfacial polymerization. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 352–366, 2000 A novel segmented block copolymer, containing polyethylene glycol segment and GlyAlaGlyAla sequence derived from B. mori silk, has been prepared. The phenoxathiin‐templated parallel β‐sheets self‐assembled in an antiparallel fashion in the solid state resulting in a phase‐separation as evidenced by FTIR, TEM, and DSC.