Two-Dimensional Polymers with Random Short-Range Interactions

TL;DR

This study investigates two-dimensional self-avoiding polymers with random charges, revealing a temperature-dependent collapse transition and characterizing the polymer's size scaling at criticality, with no signs of low-temperature freezing.

Contribution

It introduces a detailed analysis of charge-disordered 2D polymers, identifying a collapse transition and quantifying size scaling behavior at the transition point.

Findings

Polymer undergoes a collapse transition at temperature T_θ.

The critical size exponent ν_θ is approximately 0.60.

No evidence of freezing at low temperatures.

Abstract

We use complete enumeration and Monte Carlo techniques to study two-dimensional self-avoiding polymer chains with quenched ``charges'' $\pm 1$. The interaction of charges at neighboring lattice sites is described by $q_i q_j$. We find that a polymer undergoes a collapse transition at a temperature $T_{\theta}$, which decreases with increasing imbalance between charges. At the transition point, the dependence of the radius of gyration of the polymer on the number of monomers is characterized by an exponent $\nu_{\theta} = 0.60 \pm 0.02$, which is slightly larger than the similar exponent for homopolymers. We find no evidence of freezing at low temperatures.