Electrostatically enhanced second and third virial coefficients, viscosity, and interparticle correlations for linear polyelectrolytes

The use of an automatic, continuous mixing (ACM) technique, coupled with multiangle static light scattering, refractometric, and viscometric detectors allowed detailed measurements of electrostatic effects in polyelectrolyte solutions to be made while varying ionic strength [I], and polyelectrolyte concentration. A linear polyelectrolyte, sodium hyaluronate (HA) was used. The behavior of second and third virial coefficients, A(2) and A(3), the angular scattering envelope, and the reduced viscosity were determined simultaneously. The crossover regime from where interparticle effects dominate the scattering to where single particle form factors dominate is clearly seen and is rationalized by a simple pair correlation function. Good agreement is found for polymer dimensions and A(2) Using a combination of electrostatic persistence length and electrostatic excluded volume theories, with no adjustable parameters. The contribution to [I] from the HA counterions is observed via the electroviscous effect, a reduced viscosity crossover phenomenon, and an unusual scattering minimum vs polyelectolyte concentration at low [I].