Solenoids and Plectonemes in stretched and twisted elastomeric filaments, 

Solenoids and Plectonemes in stretched and twisted elastomeric filaments

Solenoids and Plectonemes in stretched and twisted elastomeric filaments,  A. Ghatak and L. Mahadevan,  Physical Review Letters  , 95, 057801, 2005.
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Abstract

We study the behavior of a naturally straight highly extensible elastic filament subjected to large
extensional and twisting strains. We find that two different phases can coexist for a range of parameter
values: the plectoneme and the solenoid. A simple theory based on a neo-Hookean model for the material
of the filament and accounting for the slender geometry suffices to explain these observations, and leads to
a phase diagram that is consistent with observations. Extension and relaxation experiments on these
phases show the presence of large hysteresis loops and sawtoothlike force-displacement curves which are
different for the plectoneme and the solenoid.