Nanoscale X-Ray Diffraction Study on Hierarchical Structure of Bagworm Silk with Local Mesoscale Nanofibrillar Organization

Silk threads spun by bagworms (Psychidae) show superb mechanical properties, resulting from a highly ordered fibrillar organization. In order to clarify the structural localization in a single thread, we performed nanoscale SAXS/WAXS at the ID13 beamline during SC5011. For an about 5um thick fiber we resolved its ca. 200 nm thick sericin layer and the nanofibrillar organization of its core. We showed that much weaker scattering from mesoscale nanofibrillar self-assembly is only revealed in cross-sections lacking sericin background scattering. In this continuation proposal, we aim clarifying further details of the mesoscale nanofibrillar organization, such as structural localization both along the radial and longitudinal directions, lattice-features of nanofibrillar packing and the effect of degumming treatment on it. For achieving these purposes, we will prepare thin sections of various thickness and analyse them by scanning SAXS/WAXD with focus of at least 200 nm (hopefully 50 nm).