Dresden 2009 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: Liquids

CPP 7.3: Vortrag

Montag, 23. März 2009, 18:30–18:45, ZEU 160

Charge transport and glassy dynamics in ionic liquids — •Joshua Sangoro, Ciprian Iacob, Anatoli Serghei, Sergej Naumov, Jorg Kärger, and Friederich Kremer — Institute of Experimental Physics I, University of Leipzig, Linnéstr. 5, 04103, Leipzig, Germany

Charge transport and glassy dynamics of a variety of glass-forming ionic liquids (ILs) are investigated in a wide frequency and temperature range by means of Broadband Dielectric Spectroscopy(BDS), Pulsed Field Gradient Nuclear Magnetic Resonance (PFG NMR), AC Calorimetry, Differential Scanning Calorimetry and Rheology. While the absolute values of dc conductivity and viscosity vary over more than 11 decades with temperature and upon systematic structural variation of the ILs, quantitative agreement is found between the characteristic frequency of charge transport and the structural a-relaxation. This is traced back to dynamic glass transition assisted hopping as the underlying mechanism of charge transport. A novel approach is applied to extract diffusion coefficients from BDS spectra in quantitative agreement with PFG NMR values but in a much broader range. References: [1] J. R. Sangoro, A. Serghei, S. Naumov, P. Galvosas, J. Kärger, C. Wespe, F.Bordusa, and F. Kremer, Phys. Rev. E 77, 051202 (2008); J. R. Sangoro et al, J. Chem. Phys. 128, 214509 (2008);J.R. Sangoro, C. Iacob, A. Serghei,C. Friedrich, F. Kremer, Phys. Chem. Chem. Phys., In press.