Universal shape characteristics for the mesoscopic polymer chain via dissipative particle dynamics

TL;DR

This study uses dissipative particle dynamics to analyze the shape characteristics of polymer chains in good solvents, confirming scaling laws and shape distributions consistent with theoretical and Monte Carlo results.

Contribution

It provides a mesoscopic simulation approach to characterize polymer shapes, validating scaling laws and shape distributions against theoretical and lattice Monte Carlo data.

Findings

Scaling laws for end-to-end distance and gyration radius hold for N≥10.

Shape characteristics become independent of chain length for N≥10.

Shape distributions resemble lattice Monte Carlo results.

Abstract

In this paper we study the shape characteristics of a polymer chain in a good solvent using a mesoscopic level of modelling. The dissipative particle dynamics simulations are performed in the $3D$ space at a range of chain lengths $N$. The scaling laws for the end-to-end distance and gyration radius are examined first and found to hold for $N\geq 10$ yielding reasonably accurate value for the Flory exponent $\nu$. Within the same interval of chain lengths, the asphericity, prolateness, size ratio and other shape characteristics of the chain are found to become independent of $N$. Their mean values are found to agree reasonably well with the respective theoretical results and lattice Monte Carlo simulations. Broad probability distributions for the shape characteristics are found resembling in form the results of lattice Monte Carlo simulations. By means of analytic fitting of these distributions the most probable values for the shape characteristics are found to supplement their mean values.