REPTATION IN SEMIDILUTE SOLUTIONS OF WORMLIKE POLYMERS

We report fringe pattern fluorescence bleaching measurements of the self-diffusion coefficient of the wormlike polysaccharide xanthan at various molecular weights in aqueous solutions. Three distinguished concentration regimes are found: the dilute regime, the semidilute regime, and a new “concentrated” regime characteristic of wormlike polymers at concentrations where the intermolecular correlation length becomes smaller than the persistence length. We give simple scaling arguments that are consistent with the main trends in the data as a function of concentration and chain length and provide a fair estimate for the self-diffusion constant and the crossover concentrations. © 1990, American Chemical Society. All rights reserved.