ELECTROSTATIC CONTRIBUTIONS TO THE VISCOSITIES AND DIFFUSION-COEFFICIENTS OF MACRO-ION SOLUTIONS

Electrostatic effects on the viscosity, the static structure factor, and the macroion diffusion coefficient are investigated in solutions of charged bovine serum albumin (BSA). We show that decreasing the ionic strength leads to a decrease in the static structure factor and an increase in the measured diffusion coefficient, but not by the same factor. We show further that the increase in the solution viscosity in the limit of low salt is due primarily to macroion-macroion interactions. The magnitude of the viscosity increase is not sufficient to explain the diffusion-structure factor data unless the long-range nature of the electrostatic interaction is taken into account. © 1979 American Institute of Physics.