Longitudinal Response of Confined Semiflexible Polymers

TL;DR

This paper investigates how confinement affects the nonlinear tension dynamics of semiflexible polymers, revealing an effective prestress influence and discovering a superlinear growth law during free relaxation.

Contribution

It provides a theoretical analysis of confined semiflexible polymer tension dynamics, introducing the concept of effective prestress and identifying a superlinear relaxation law.

Findings

Confinement influences nonlinear polymer dynamics as an effective prestress.

A superlinear t^(9/8) growth law is found for free relaxation.

The study offers scaling laws and analytical theory for various experimental setups.

Abstract

The longitudinal response of single semiflexible polymers to sudden changes in externally applied forces is known to be controlled by the propagation and relaxation of backbone tension. Under many experimental circumstances, realized, e.g., in nano-fluidic devices or in polymeric networks or solutions, these polymers are effectively confined in a channel- or tube-like geometry. By means of heuristic scaling laws and rigorous analytical theory, we analyze the tension dynamics of confined semiflexible polymers for various generic experimental setups. It turns out that in contrast to the well-known linear response, the influence of confinement on the non-linear dynamics can largely be described as that of an effective prestress. We also study the free relaxation of an initially confined chain, finding a surprising superlinear t^(9/8) growth law for the change in end-to-end distance at short times.