1 research outputs found
Rough Fibrils Provide a Toughening Mechanism in Biological Fibers
Spider silk is a fascinating
natural composite material. Its combination
of strength and toughness is unrivalled in
nature, and as a result, it has gained considerable
interest from the medical, physics,
and materials communities. Most of this
attention has focused on the one to tens of
nanometer scale: predominantly the primary
(peptide sequences) and secondary (β sheets,
helices, and amorphous domains) structure, with some insights into tertiary structure (the
arrangement of these secondary structures) to describe the origins of the mechanical and
biological performance. Starting with spider silk, and relating our findings to collagen fibrils,
we describe toughening mechanisms at the hundreds of nanometer scale, namely, the fibril
morphology and its consequences for mechanical behavior and the dissipation of energy.
Under normal conditions, this morphology creates a nonslip fibril kinematics, restricting
shearing between fibrils, yet allowing controlled local slipping under high shear stress,
dissipating energy without bulk fracturing. This mechanism provides a relatively simple target
for biomimicry and, thus, can potentially be used to increase fracture resistance in synthetic
materials