X-ray diffraction on spider silk during controlled extrusion under a synchrotron radiation X-ray beam

The structure of a single thread of Nephila edulis silk has been studied by in situ X-ray diffraction from a living spider. A systematic increase of o rientational order with increasing silking speed up to 40 mm s(-1) was obse rved. Within a few mm from the spinnerets exit, crystalline domains with a beta -poly(L-alanine) structure were observed. The data also suggest an inc rease in crystalline fraction in the immediate vicinity of the spigot exit.