SELF-DIFFUSION AND PROBE DIFFUSION IN DILUTE AND SEMIDILUTE AQUEOUS-SOLUTIONS OF DEXTRAN

Tracer diffusion proceses in polymeric solutions of dextran in both the dilute and semidilute regimes were investigated by the fluorescence photobleaching recovery technique. The molecular weight of the matrices covered the range from 40 kDa to 2 MDa. The tracer species consisted of fluorescein-labeled dextrans of molecular weights 40 and 150 kD, fluorescein-labeled polystyrene spheres of 38-nm diameter, and fluorescein (molecular weight of 332 Da). The viscosity of selected solutions was measured with capillary viscosimeters. We report here an extensive set of experimental data on diffusion processes and viscosity, obtained from a consistent set of samples. Comparison of our data with some of the current models is presented.