Statistical mechanics of double-helical polymers

TL;DR

This paper presents a geometric model for double-helical polymers, analyzing their statistical mechanics through analytical and simulation methods, revealing a temperature-dependent helix melting transition and force-dependent mechanical behavior.

Contribution

It introduces a unified energy-scale model for bending and twisting rigidity, and explores the thermal and mechanical properties of double-helical polymers.

Findings

Helix melts at a specific temperature T_c.

Below T_c, the polymer maintains a helical structure.

At high forces, the polymer's behavior deviates from worm-like chain models.

Abstract

We introduce a simple geometric model for a double-stranded and double-helical polymer. We study the statistical mechanics of such polymers using both analytical techniques and simulation. Our model has a single energy-scale which determines both the bending and twisting rigidity of the polymer. The helix melts at a particular temperature T_c below which the chain has a helical structure and above which this structure is disordered. Under extension we find that for small forces, the behaviour is very similar to worm-like chain behaviour but becomes very different at higher forces.