Simulating flexible polymers in a potential of randomly distributed hard disks

TL;DR

This study uses computer simulations to analyze how flexible polymers behave in a two-dimensional environment with randomly distributed hard disks, revealing significant effects of high-density disorder on polymer configurations.

Contribution

It introduces a combined use of growth algorithms and multicanonical Monte Carlo methods to study polymer behavior in complex disordered environments.

Findings

Disorder has minimal effect at low densities

High-density disorder significantly alters polymer configurations

Scaling behavior of end-to-end distance depends on monomer number

Abstract

We perform equilibrium computer simulations of a two-dimensional pinned flexible polymer exposed to a quenched disorder potential consisting of hard disks. We are especially interested in the high-density regime of the disorder, where subtle structures such as cavities and channels play a central role. We apply an off-lattice growth algorithm proposed by Garel and Orland [J. Phys. A 23, L621 (1990)], where a distribution of polymers is constructed in parallel by growing each of them monomer by monomer. In addition we use a multicanonical Monte Carlo method in order to cross-check the results of the growth algorithm. We measure the end-to-end distribution and the tangent-tangent correlations. We also investigate the scaling behavior of the mean square end-to-end distance in dependence of the monomer number. While the influence of the potential in the low-density case is merely marginal, it dominates the configurational properties of the polymer for high densities.