Regular Article – Soft Matter
Writhing and hockling instabilities in twisted elastic fibers
Department of Physics and Astronomy, McMaster University, 1280 Main Street West, L8S 4M1, Hamilton, ON, Canada
2 UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005, Paris, France
Accepted: 6 October 2021
Published online: 14 December 2021
The buckling and twisting of slender, elastic fibers is a deep and well-studied field. A slender elastic rod that is twisted with respect to a fixed end will spontaneously form a loop, or hockle, to relieve the torsional stress that builds. Further twisting results in the formation of plectonemes—a helical excursion in the fiber that extends with additional twisting. Here we use an idealized, micron-scale experiment to investigate the energy stored, and subsequently released, by hockles and plectonemes as they are pulled apart, in analogy with force spectroscopy studies of DNA and protein folding. Hysteresis loops in the snapping and unsnapping inform the stored energy in the twisted fiber structures.
© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2021