Origin of the variability of the mechanical properties of silk fibers: 4. Order/crystallinity along silkworm and spider fibers. (17th September 2014)

• Record Type: Journal Article
• Authors: Wojcieszak, Marine; Percot, Aline; Noinville, Sylvie; Gouadec, Gwénaël; Mauchamp, Bernard; Colomban, Philippe
• Is Part Of: Journal of Raman spectroscopy. Volume 45:Number 10(2014:Oct.)
• Page Start: 895
• Page End: 902
• Publication Date: 2014-09-17
• Subjects: Raman spectroscopy -- Periodicals; 535.846
• DOI: 10.1002/jrs.4579
• Languages: English
• ISSNs: 0377-0486

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The poor crystallinity of proteic fibers has fuelled an ongoing debate over their exact organization. We present a full‐range Raman comparison of <italic>Nephila madagascariensis</italic> spider and <italic>Bombyx mori</italic> silkworm silks that sheds some new light on that matter. On the one hand, a large variability is observed along the fibers in the −200 to 200 cm⁻¹ spectral window, which is sensitive to the long‐range order signature of polyamide chains. This questions the validity of previous literature data considering silk fiber as a homogeneous material. On the other hand, the 'amide I' band is almost independent of the targeted point, which sets a limit to this widely used structure probe. In‐line mapping of the fibers showed that the extension of the ordered zones ranges between 1 and 3 µm. The correlation between the macromechanical behavior (the stress–strain curves) and the nanomechanics (Raman low wavenumber signatures) under controlled tensile strain demonstrates a Prevorsek's type microstructure: the macromolecular chains belong to both ordered and amorphous 'regions'. Copyright © 2014 John Wiley &amp; Sons, Ltd.</p> </abstract>