Elasticity of semiflexible polymers with and without self-interactions

TL;DR

This paper introduces a new force-extension formula for semiflexible polymers derived from the worm-like chain model, which accurately fits experimental and simulation data, especially at high forces and temperatures above the theta point.

Contribution

The paper presents a novel analytical formula for polymer elasticity that accounts for self-interactions, improving the understanding of polymer stretching behavior.

Findings

The new formula fits experimental data well.

Agreement with simulations is good above the theta temperature.

A plateau appears at low temperatures and forces.

Abstract

A {\it new} formula for the force vs extension relation is derived from the discrete version of the so called {\it worm like chain} model. This formula correctly fits some recent experimental data on polymer stretching and some numerical simulations with pairwise repulsive potentials. For a more realistic Lennard-Jones potential the agreement with simulations is found to be good when the temperature is above the $\theta$ temperature. For lower temperatures a plateau emerges, as predicted by some recent experimental and theoretical results, and our formula gives good results only in the high force regime. We briefly discuss how other kinds of self-interactions are expected to affect the elasticity of the polymer.