Simulation of Polyelectrolytes in Solution Using Dissipative Particle Dynamics in the Grand Canonical Ensemble: Interaction Strength and Salt Effects

TL;DR

This study uses dissipative particle dynamics in the grand canonical ensemble to simulate polyelectrolyte solutions, examining how salt concentration and interaction strength influence their structure and behavior.

Contribution

It introduces a mesoscopic DPD method with Ewald summation for electrostatics in the grand canonical ensemble, providing new insights into polyelectrolyte and electrolyte solutions.

Findings

Good agreement with literature for electrostatic force calculations

Salt and solvent quality significantly affect polyelectrolyte conformation

Electrostatic interactions are crucial in charged systems

Abstract

We have studied a bulk electrolyte, and polyelectrolyte solutions with surfactants or multivalent salt with the explicit presence of counterions and solvent molecules by means of the mesoscopic dissipative particle dynamics (DPD) method in the Grand Canonical ensemble. The electrostatic interactions are calculated using the Ewald sum method and the structure of the fluid is analyzed through the radial distribution function between charged particles. The results are in very good agreement with those reported in the literature using a different method for the calculation of the electrostatic forces, and with those obtained using DPD in the canonical ensemble. We also studied the salt dependent conformation of polyelectrolyte solutions as a function of the solvent quality, and analyzed the electrostatic interaction strength dependence of dilute flexible polyelectrolytes in solution. For the complex systems mentioned above, the electrostatic interactions and the solvent quality play a key role in understanding phenomena that do not occur in noncharged systems.