New insight into “polyelectrolyte effect”

A new insight into “polyelectrolyte effect” which referred to the reduced viscosity of polyelectrolyte upon dilution resulting from the intra-molecular electrostatic repulsion was proposed, depending on the results by the authors concerning the viscosity theory of polymer solutions through theoretical and experimental methods. The results reveal that the abnormal viscosity behaviors of polyelectrolytes as well as neutral polymers in dilute solution region are ascribed to the interface effects. The polymeric solutes are readily adsorbed on the viscometer capillary wall surface, which greatly influences the viscosity measurement of polymer solutions, and results in apparent abnormal viscosity behavior. It is suggested that the so-called “abnormal” viscosity data, difficult to deal with and ignored by previous researchers, are not actually abnormal, but contain a lot of structural information on polymer both on the capillary wall and in solutions. In the present article, recent progresses in the studies on the viscosity behaviors of various polyelectrolytes are summarized, mainly depending on the findings of the authors and their collaborators involving synthetic polyelectrolytes, natural polyelectrolytes and amphoteric proteins.