Eur. Phys. J. E (2008) 27: 229-242
https://doi.org/10.1140/epje/i2008-10374-7

Regular Article

Diffraction from the β -sheet crystallites in spider silk

¹ Institut für Theoretische Physik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
² Institut für Röntgenphysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
³ Max-Planck-Institut für Dynamik und Selbstorganisation, Bunsenstrasse 10, 37073, Göttingen, Germany

^* e-mail: ulrich@theorie.physik.uni-goettingen.de

Received: 18 March 2008
Revised: 11 July 2008
Published online: 10 October 2008

Abstract

We analyze the wide-angle X-ray scattering from oriented spider silk fibers in terms of a quantitative scattering model, including both structural and statistical parameters of the β -sheet crystallites of spider silk in the amorphous matrix. The model is based on kinematic scattering theory and allows for rather general correlations of the positional and orientational degrees of freedom, including the crystallite’s size, composition and dimension of the unit cell. The model is evaluated numerically and compared to experimental scattering intensities allowing us to extract the geometric and statistical parameters. We show explicitly that for the experimentally found mosaicity (width of the orientational distribution) inter-crystallite effects are negligible and the data can be analyzed in terms of single-crystallite scattering, as is usually assumed in the literature.