Viscometric behavior of dilute polyelectrolytes. Role of electrostatic interactions

This paper deals with the investigation of the electroviscous effects on sodium hyaluronate aqueous solutions. Dilution of a polyelectrolyte in water or low salt concentration solvent gives a reduced viscosity passing through a maximum whose position corresponds to a polymer concentration directly related to the ionic concentration. Independently of the molecular weight when isoionic dilution is performed, the conformation is preserved and the intrinsic viscosity corresponding to the adopted ionic concentration is obtained as soon as the concentration range corresponds to the dilute domain. At end the model previously proposed to take into account the role of the electrostatic interactions on the conformation is adopted to interpret, with a good agreement, the data of intrinsic viscosity versus ionic concentration.