Probing the impact of linear deformation on local meso-scale nanofibrillar self-assembly of bagworm silk by X-ray nanodiffraction

Silk threads spun by bagworms (Psychidae) show superb mechanical properties, resulting from a highly ordered fibrillar organization. The SAXS/WAXD analyses using nanoscale X-ray beam for a single bagworm silk (performed at ESRF, ID-13 beamline during SC5011and 5259) resolved an anisotropic structural feature made of a radial gradient in diameters of mesoscale nanofibrillar assembly. However, influence of such radial heterogeneity of mesoscale nanofibrillar assembly on the mechanical properties of bagworm silk has not been known. In order to clarify the influence of radial structural heterogeneity on the mechanical properties, we will conduct a dynamic SAXS/WAXD measurements using nanoscale X-ray beam during the single fiber stretching in this proposal, and we aim clarifying how the radial heterogeneity of mesoscale structural order affect on the superb mechanical properties of bagworm silk.

袋蛾（Psychidae科）纺制的丝线具有优异的力学性能，这源于其高度有序的纤维状结构。利用纳米级X射线束对单根袋蛾丝线开展的SAXS/WAXD分析（在ESRF的ID-13光束线、SC5011和5259实验期间完成）揭示了一种各向异性结构特征（anisotropic），该特征表现为介观尺度纳米纤维组件直径的径向梯度分布。然而，介观纳米纤维组件的这种径向异质性（radial heterogeneity）对袋蛾丝线力学性能的影响尚未明确。本研究计划将通过在单根纤维拉伸过程中利用纳米级X射线束进行动态SAXS/WAXD测量，阐明径向结构异质性对力学性能的影响，旨在揭示介观结构有序性的径向异质性如何作用于袋蛾丝线的优异力学性能。