Bending and buckling of spider and silkworm silk

Spider silk has outstanding mechanical properties despite being spun at close to ambient temperatures and pressures using water as the solvent. And the mechanical properties are predicted to be sensitive to details of their structure and to the presence of defects, which means that measurements on single silk are essential to establish these properties. Using a unique axial compression bending measurement, we have performed intricate buckling of single silk fibres. Test output is a force-displacement cure, from which the flexural rigidity and equivalent bending modulus are determined. From it we observe a range of responses to this bending deformation, which together suggest that silks are remarkably flexible and resilient.