DIELECTRIC BEHAVIOR OF POLYELECTROLYTE SOLUTIONS - THE ROLE OF PROTON FLUCTUATION

The dielectric properties of chitosan in aqueous solutions have been measured as a function of the degree of ionization in the frequency range from 1 kHz to 10 MHz. The dielectric spectra have been analyzed in terms of two contiguous dispersions described by a Cole-Cole and Debye relaxation function. The dependence of the dielectric parameters (dielectric increments and relaxation frequencies) on the degree of ionization cannot be understood simply as a result of polarization of the ionic atmosphere around the polyion, on the basis of the polyelectrolytic counterion fluctuation model. The present results suggest that protonic transport through the ionized sites of the polymer is the dominant mechanism responsible for the overall observed dielectric behavior.