Networks of helix-forming polymers

TL;DR

This paper studies how networks of helix-forming polymers respond to external strain, revealing that both stretching and compression can increase helical content due to temperature-dependent helix-coil transitions.

Contribution

It introduces a model for cross-linked helix-forming polymer networks and analyzes how external deformation influences their helical content.

Findings

Elongation can increase helical domains under certain conditions.

Compression can also promote helix formation.

The coupling between strain and helix content is significant in these networks.

Abstract

Biological molecules can form hydrogen bonds between nearby residues, leading to helical secondary structures. The associated reduction of configurational entropy leads to a temperature dependence of this effect: the "helix-coil transition". Since the formation of helices implies a dramatic shortening of the polymer dimensions, an externally imposed end-to-end distance R affects the equilibrium helical fraction of the polymer and the resulting force- extension curves show anomalous plateau regimes. In this article, we investigate the behaviour of a cross-linked network of such helicogenic molecules, particularly, focusing on the coupling of the (average) helical content present in a network to the externally imposed strain. We show that both an elongation and compression can lead to an increase in helical domains under appropriate conditions.