Pressure-Dependent FTIR-Spectroscopy on the Counterbalance between External and Internal Constraints in Spider Silk of Nephila pilipes
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- 作者：Arthur Markus Anton ; Wilhelm Kossack ; Christof Gutsche ; Roxana Figuli (Ene) ; Periklis Papadopoulos ; Jihaan Ebad-Allah ; Christine Kuntscher ; Friedrich Kremer
- 刊名：Macromolecules
- 出版年：2013
- 出版时间：June 25, 2013
- 年：2013
- 卷：46
- 期：12
- 页码：4919-4923
- 全文大小：343K
- 年卷期：v.46,no.12(June 25, 2013)
- ISSN：1520-5835
文摘
Nanocrystals composed mainly of 尾-sheet polyalanine are responsible for the high toughness of major ampullate (dragline) spider silk. Fourier-transform infrared (FTIR) spectroscopy is employed to study their response to (i) uniaxial stress and (ii) hydrostatic pressure. In the former a red shift and in the latter a blue shift of the vibration of polyalanine 尾-sheets at 965 cm鈥? occurred. In both cases, a linear dependence is observed, which bends off for hydrostatic pressure greater than 1.4 GPa and is fully reversible up to 7 GPa. The seamless connection of negative and positive pressure regimes corroborate quantitatively our structural model of spider silk as composed of prestressed alanine-rich nanocrystals embedded in a glycine-rich amorphous matrix. It is also confirmed that nanocrystals withstand high pressures without undergoing structural transition or deteriorating their mechanical properties.