Stretching dynamics of semiflexible polymers

TL;DR

This paper presents a unified theoretical analysis of the nonequilibrium stretching dynamics of semiflexible biopolymers, clarifying tension propagation and relaxation processes through a blob picture and numerical validation.

Contribution

It introduces a comprehensive theory that consolidates and extends previous scaling laws for tension propagation in stretched semiflexible polymers.

Findings

Derived new scaling laws for tension propagation speed.

Provided a physical explanation using the blob picture.

Supported results with numerical solutions of coarse-grained equations.

Abstract

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 $f_\text{pre}$ that is suddenly exposed to a different external force $f_\text{ext}$ 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.