  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.
