Shape Phase Transition of Polyampholytes in Two Dimensions

TL;DR

This study investigates how two-dimensional polyampholytes change shape from extended to globular states at different temperatures and charges, revealing a critical charge threshold influenced by interaction range and polymer size.

Contribution

It introduces a Monte Carlo simulation approach to analyze shape transitions in 2D polyampholytes, highlighting the dependence of critical charge on interaction law and polymer length.

Findings

Polymers become globular below a critical charge $Q_c$.

Critical charge is inversely related to interaction range.

Critical charge scales linearly with polymer size $N$ in the thermodynamic limit.

Abstract

We have studied the transition in shape of two dimensional polyampholytes using Monte Carlo simulation. We observe that polymers with randomly charged monomers get into a globular shape at lower temperatures, provided that their total charge is below a critical value $Q_c$. Collapse into globular form happens for all forms of force law, but the critical charge depends on the form of the force law, inversely dependent on the range of interaction. The value of the critical charge is proportional to $N$, the size of the polymer, in the thermodynamic limit. PACS numbers: 36.20.-r, 35.20.Bm, 64.60.-i