Stretching dynamics of semiflexible polymers

We analyze the nonequilibrium dynamics of single inextensible
semiflexible biopolymers as stretching forces are applied at the
ends. Based on different (contradicting) heuristic arguments,
various scaling laws have been proposed for the propagation speed
of the backbone tension which is induced in response to stretching.
Here, we employ a newly developed unified theory to systematically
substantiate, restrict, and extend these approaches. Introducing
the practically relevant scenario of a chain equilibrated under
some prestretching force f pre that is suddenly exposed to a
different external force f ext at the ends, we give a concise
physical explanation of the underlying relaxation processes by
means of an intuitive blob picture. We discuss the corresponding
intermediate asymptotics, derive results for experimentally
relevant observables, and support our conclusions by numerical
solutions of the coarse-grained equations of motion for the
tension.