A Theoretical Model for Polyelectrolyte Solutions with Salt Effect

Polyelectrolyte (PE) solutions are endowed with both viscous and elastic properties that differ significantly from uncharged polymer solutions. Scaling laws for predicting their viscosity and relaxation time are often based on specific assumptions such as the presence of a theta-solvent, so that the results sometimes fail to explain the conformation or viscoelastic behavior of PE solutions in certain concentration regimes. Here, we use the self-consistent mean-field theory and study the conformation, viscosity and relaxation time of semi-dilute polyelectrolyte solutions in good solvents. We develop a general model that fits well with experimental results and includes excluded volume and counterion screening effects as a function of salt concentration.