Abstract
The dependence of viscosity of dilute solutions containing high-and low-molecular-mass electrolytes on solute concentrations was studied for completely and partially ionizing polyelectrolytes used as an example. The viscosity of solutions of the completely ionizing polyelectrolytes is described by the generalized Fuoss relationship derived earlier. However, the viscosity of solutions of the incompletely ionizing polyelectrolytes may substantially deviate from the relations derived on the basis of this expression. On the basis of the electrostatic theory of swelling, it was shown that the region of the distinct polyelectrolyte effect corresponds to practically complete volume filling by macromolecular coils. The viscosity of a polyelectrolyte solution is determined by two factors, the electrostatic interaction of coils that occur at a distance on the order of the Debye length apart from one another and the coil deformability. The former factor can completely be described through the similarity criterion corresponding to the generalized Fuoss law, and the latter factor requires that a change in the electrostatic persistence length should be taken into account, as this quantity is directly affected by the degree of charging of the macromolecule backbone.