Lattice model for cold and warm swelling of polymers in water

TL;DR

This paper introduces a lattice model to simulate polymer-water interactions, revealing temperature-dependent conformational transitions that resemble protein folding and unfolding behaviors.

Contribution

The study presents a novel lattice model capturing the swelling and collapsing transitions of polymers in water, analogous to protein behavior.

Findings

Polymer transitions from non-compact to compact at intermediate temperatures.

Polymer swells again at higher temperatures, indicating a reentrant behavior.

Model behavior closely resembles protein folding/unfolding phenomena.

Abstract

We define a lattice model for the interaction of a polymer with water. We solve the model in a suitable approximation. In the case of a non-polar homopolymer, for reasonable values of the parameters, the polymer is found in a non-compact conformation at low temperature; as the temperature grows, there is a sharp transition towards a compact state, then, at higher temperatures, the polymer swells again. This behaviour closely reminds that of proteins, that are unfolded at both low and high temperatures.