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Study on secondary structural transition of nano‐TiO 2 modified silk fibroin composite films by two‐dimensional Raman correlation spectroscopy and solid‐state 13 C‐NMR spectroscopy
Author(s) -
Zhu Hailin,
Zhang Fangfang,
Feng Xinxing,
Zhang Jianchun,
Chen Jianyong
Publication year - 2015
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.22920
Subject(s) - fibroin , silk , materials science , random coil , raman spectroscopy , magic angle spinning , composite number , nano , spectroscopy , composite material , nuclear magnetic resonance spectroscopy , crystallography , circular dichroism , chemistry , organic chemistry , physics , optics , quantum mechanics
By a sol–gel processing, the nano‐TiO 2 / silk fibroin (SF) composite films were prepared. One‐dimensional (1D) Raman, two‐dimensional (2D) correlation Raman spectroscopy, and 13 C cross‐polarization magic‐angle‐spinning nuclear magnetic resonance ( 13 C CP‐MAS NMR) were used to characterize the structural evolution of SF as the nano‐TiO 2 content increased from 0 to 0.4 wt%. The experimental data demonstrated that the secondary structures in the pure SF film and nano‐TiO 2 / silk fibroin (SF) composite films were random coil, α‐helix and β‐sheet structures. The nano‐TiO 2 particles formed in the SF films might induce partial structural transitions from random coil and Silk I (α‐helix) to Silk II ( β ‐sheet). The transition identified by 2D‐Raman correlation spectra was the following order: silk I‐like structure, silk I (α‐helical structure), Silk II‐like structure, and Silk II (β‐sheet structure). POLYM. COMPOS., 36:121–127, 2015. © 2014 Society of Plastics Engineers