Viscosity from ternary mixtures of two weakly charged polyelectrolytes in solution

The mode-mode coupling approximation (MMCA) is applied to describe the behavior of the reduced viscosity η_r from ternary mixtures of two weakly charged polyelectrolytes in solution. Similarly (ε = +1) as well as oppositely (ε = −1) weakly charged polyions are discussed in this work. The variation of η_r with the total polyelectrolyte concentration C_T exhibits a peak. The position and the height of this peak show for a given concentration of added salt C_S a sensitive variation with: the charge parameters (degrees of ionization) f₁ and f₂ of both polyelectrolytes, the proportion of polyelectrolyte 1 within the mixture (x = C₁/C_T) and the Flory interaction parameter χ_F between monomeric units of different species. This calculation is presented within the framework of the Rouse model where no hydrodynamic interactions are taken into account.