X-ray diffraction study of nanocrystalline and amorphous structure within major and minor ampullate dragline spider silks

Sujatha Sampath, Thomas Isdebski, Janelle E. Jenkins, Joel V. Ayon, Robert W. Henning, Joseph P R O Orgel, Olga Antipoa, Jeffery Yarger

Research output: Contribution to journalArticlepeer-review

96 Scopus citations

Abstract

Synchrotron X-ray micro-diffraction experiments were carried out on Nephila clavipes (NC) and Argiope aurantia (AA) major (MA) and minor ampullate (MiA) fibers that make up dragline spider silk. The diffraction patterns show a semi-crystalline structure with β-poly(l-alanine) nanocrystallites embedded in a partially oriented amorphous matrix. A superlattice reflection 'S' diffraction ring is observed, which corresponds to a crystalline component larger in size and is poorly oriented, when compared to the β-poly(l- alanine) nanocrystallites that are commonly observed in dragline spider silks. Crystallite size, crystallinity and orientation about the fiber axis have been determined from the wide-angle X-ray diffraction (WAXD) patterns. In both NC and AA, the MiA silks are found to be more highly crystalline, when compared with the corresponding MA silks. Detailed analysis on the amorphous matrix shows considerable differences in the degree of order of the oriented amorphous component between the different silks studied and may play a crucial role in determining the mechanical properties of the silks.

Original languageEnglish (US)
Pages (from-to)6713-6722
Number of pages10
JournalSoft Matter
Volume8
Issue number25
DOIs
StatePublished - Jul 7 2012

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics

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