Collapse of Randomly Self-Interacting Polymers

TL;DR

This study investigates how randomly charged self-interacting polymers collapse, revealing a transition from extended to compact states influenced by charge asymmetry and interaction strength.

Contribution

It introduces a combined enumeration and Monte Carlo approach to analyze the collapse transition in randomly charged self-avoiding walks, highlighting the effects of charge asymmetry.

Findings

Polymer collapses at a temperature ~1.2v_0 for symmetric charges.

Collapse temperature decreases with increasing charge asymmetry.

Transition from self-avoiding to compact state depends on interaction strength and charge distribution.

Abstract

We use complete enumeration and Monte Carlo techniques to study self--avoiding walks with random nearest--neighbor interactions described by $v_0q_iq_j$, where $q_i=\pm1$ is a quenched sequence of ``charges'' on the chain. For equal numbers of positive and negative charges ($N_+=N_-$), the polymer with $v_0>0$ undergoes a transition from self--avoiding behavior to a compact state at a temperature $\theta\approx1.2v_0$. The collapse temperature $\theta(x)$ decreases with the asymmetry $x=|N_+-N_-|/(N_++N_-)$