The Viscosity of Polyelectrolyte Solutions and its Dependence on their Persistence Length, Concentration and Solvent Quality

TL;DR

This study uses numerical simulations to explore how polyelectrolyte solution viscosity depends on factors like concentration, persistence length, salt, and solvent quality, revealing key electrostatic effects and scaling regimes.

Contribution

It provides a detailed analysis of viscosity scaling in polyelectrolyte solutions under various conditions, aiding the design of tailored polyelectrolytes for complex fluid applications.

Findings

Electrostatic interactions significantly influence viscosity.

Multiple scaling regimes are identified under different solvent conditions.

Salt concentration alters the viscosity behavior.

Abstract

In this work, a comprehensive study about the influence on shear viscosity of polyelectrolyte concentration, persistence length, salt concentration and solvent quality is reported, using numerical simulations of confined solutions under stationary Poiseuille flow. Various scaling regimes for the viscosity are reproduced, both under good solvent and theta solvent conditions. The key role played by the electrostatic interactions in the viscosity is borne out when the ionic strength is varied. It is argued that these results are helpful for the understanding of viscosity scaling in entangled polyelectrolyte solutions for both rigid and flexible polyelectrolytes in different solvents, which is needed to perform intelligent design of new polyelectrolytes capable of fine tuning the viscosity in complex fluids.