Dresden 2009 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: POSTERS Dynamics and Diffusion

CPP 15.10: Poster

Dienstag, 24. März 2009, 14:00–16:30, P3

Charge transport and dynamic glass transiton in imidazole-based liquids — •Ciprian Iacob¹, Joshua Rume Sangoro¹, Anatoli Serghei¹, Sergej Naumov¹, Yasmin Korth², Jörg Kärger¹, Christian Friedrich², and Friederich Kremer¹ — ¹Institute of Experimental Physics I, University of Leipzig, Linnéstr. 5, 04103 Leipzig,Germany — ²Freiburger Materialforschungszentrum (FMF) und Institute für Makromolekulare Chemie der Albert-Ludwigs Universität Freiburg i. Br., Germany

Broadband Dielectric Spectroscopy (BDS), differential scanning calorimetry, rheology and Pulsed Field Gradient - Nuclear Magnetic Resonance (PFG - NMR) are combined to study glassy dynamics and charge transport in a homologous series of imidazole-based liquids with systematic variation of the alkyl chain length. The dielectric spectra are interpreted in terms of dipolar relaxation and conductivity contribution. By applying Einstein, Einstein-Smoluchowski and Stokes-Einstein relations, translational diffusion coefficients - in quantitative agreement with PFG NMR measurements are obtained. With increasing alkyl chain length, it is observed that the viscosity increases whereas the structural a-relaxation rate decreases in accordance with Maxwell*s relation. Between the rate we of electrical relaxation and the rate wa of the structural a-relaxation scaling is observed over more than 6 decades with a decoupling index of about 2.

References: C. Iacob et al., : J. Chem.Phys, 2008, In press; J. Sangoro et al., J. Chem.Phys.128, 214509, 2008; J. Sangoro et al., Phys. Rev. E, 051202 , 2008; F. Kremer et al., Phys. Rev .E, 54, 1996