title: Compliance of the Stokes-Einstein model and breakdown of the Stokes-Einstein-Debye model for a urea-based supramolecular polymer of high viscosity.
abstract: Impedance spectroscopy was used for the study of the static and dynamic behavior of the electrical conductivity of a hydrogen-bonded supramolecular polymer of high viscosity. The experimental data are discussed in the frame of the Stokes-Einstein and Stokes-Einstein-Debye models. It was found that the translational movement of the ions is due to normal Brownian diffusion, which was revealed by a fulfillment of Ohm's law by the electric current and a strictly exponential decay of the current after removing the electric stimulus. The dependence of the dc conductivity on the viscosity of the medium fulfills the Stokes-Einstein model quite well. An extension of the model, by including in it the conductivity relaxation time, is proposed in this paper. A breakdown of the Stokes-Einstein-Debye model is revealed by the relations of the dipolar relaxation time to the viscosity and to the dc ionic conductivity. The importance of the C=O···H-N hydrogen bonds in that breakdown is discussed.
authors.affiliation: Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, PL-60-179 Poznań, Poland. swiergiel@ifmpan.poznan.pl.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Świergiel
authors.forename: Laurent
authors.initials: L
authors.lastname: Bouteiller
authors.forename: Jan
authors.initials: J
authors.lastname: Jadżyn