Regensburg 2007 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 21: POSTER: Dynamics and Diffusion
CPP 21.11: Poster
Mittwoch, 28. März 2007, 16:00–18:30, Poster B
The dielectric properties of ionic liquids — •Joshua Sangoro1, Anatoli Serghei1, Frank Bordusa2, and Friedrich Kremer1 — 1Institut für Experimentelle Physik I, Universität Leipzig, Linnestraße 5, 04103, Leipzig, Germany — 2Max-Planck-Forschungsstelle für Enzymologie der Proteinfaltung, Weinbergweg 22, D-06120 Halle (Saale), Germany
Broadband Dielectric Spectroscopy (in the frequency range from 0.01 Hz to 10 MHz) at temperatures varying between 190 K to 330 K is employed to study molecular relaxations and ionic charge transport in ionic liquids. The former are observed at low temperatures (~ 200 K) with the latter giving rise to pronounced increases in the real part of conductivity and respectively the imaginary part of the complex dielectric function, both quantities have pronounced temperature dependence indicating the thermal activities of the underlying ionic charge transport. A remarkably low threshold of the applied electric field E is found to be at 0.3 V/cm, above which non-linear responses take place. Electrode polarization - usually neglected as an unwanted effect - contributes as well depending on various factors as geometry, concentration and the material of the electrode. The results are discussed with respect to recent and old (Debye-Falkenhagen) theories of ionic conduction.