Diffusion and Viscosity of Unentangled Polyelectrolytes

We report chain self-diffusion and viscosity data for sodium polystyrene sulfonate (NaPSS) in semidilute salt-free aqueous solutions measured by pulsed-field gradient NMR rotational rheometry, respectively. The molecular weight of NaPSS is characterized using five techniques. Relationships between Mw the intrinsic diffusion coefficient excess salt are established. These helpful accurate determination molar mass NaPSS. observed concentration dependence ? D consistent with Rouse–Zimm scaling model if monomeric friction (?) concentration-dependent. ? exceeds that expected from free-volume models diffusion, its origin remains unclear, possibly being related to electrostatic effects. Correlation blobs dilute chains equivalent end-to-end distances exhibit nearly equal coefficients, agreement scaling. Viscosity combined Rouse calculate single-chain dimensions solution, results overpredict direct SANS measurements radii gyration a factor ?1.4.