Aspects of X-ray diffraction on single spider fibers

Diffraction patterns of silk from several spider species have been obtained by synchrotron radiation using a beam size greater than or equal to 10 mu m. Single fiber diffraction patterns were obtained for fiber diameters down to a few microns. Diffraction patterns recorded with a 10 mu m wide X-ray beam displayed fiber texture. The presence of two fractions of different cr ystallinity was confirmed for a single Nephila clavipes fiber. The orientat ion distribution of the polymer chains of the crystalline fraction along th e fiber axis was found to be about 23 degrees full-width at half maximum (f whm). The azimuthal spread of the short-range order fraction was about 86 d egrees fwhm. (C) 1999 Elsevier Science B.V. All rights reserved.