Multiaxial anisotropy of spider (Araneus diadematus) cocoon silk fibres

We report a remarkable feature of the cocoon silk spun by Araneus diadematus spiders, as revealed by electron diffraction: transverse sections of the fibres exhibit significant microstructural anisotropy. Although the mechanical processes of fibre spinning and drawing are uniaxial, the spider is able to achieve multiaxial control of molecular order. In contrast, complex flow patterns are used to obtain multiaxial control of molecular order in synthetic polymer extrudates or fibres. Possible origins and consequences of the transverse anisotropy in A. diadematus cocoon silk are considered briefly.