title: Structural determination of protein-based polymer blends with a promising tool: combination of FTIR and STXM spectroscopic imaging.
abstract: Fourier transform infrared (FTIR) and scanning transmission X-ray microscopy (STXM) spectroscopic imaging techniques are introduced to determine the structure of protein-based polymer blends, using the silk fibroin/polyethylene oxide (SF/PEO) blend as a model material. We demonstrate that FTIR and STXM imaging techniques provide complementary chemical sensitivities, resolution ranges and sample thickness requirements that can enable a greater understanding of SF/PEO blend films. From the FTIR images, we find that SF shows random coil and/or helical conformation in the SF-rich domains, and β-sheet conformation in the PEO-rich matrix. In the meantime, the SF content in SF-rich domains is 74 ± 4%, and 38 ± 6% in the PEO-rich matrix from the STXM images. These findings support and give further evidence to the conclusions of the previous studies on SF/PEO blends in the literature. Our results strongly suggest that FTIR and STXM imaging techniques are two promising complementary approaches for the study of phase behaviour and molecular conformation in protein-based polymer blend materials.
authors.affiliation: State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433, People's Republic of China. chenx@fudan.edu.cn.
authors.forename: Shengjie
authors.initials: S
authors.lastname: Ling
authors.forename: Zeming
authors.initials: Z
authors.lastname: Qi
authors.forename: Benjamin
authors.initials: B
authors.lastname: Watts
authors.forename: Zhengzhong
authors.initials: Z
authors.lastname: Shao
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D012831:Bombyx / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D005349:Fibroins / Q000737:chemistry*; D044367:Phase Transition; D011092:Polyethylene Glycols / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D011092:Polyethylene Glycols; D005349:Fibroins