Berlin 2015 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 19: Glasses and Glass Transition II (CPP with DF/DY)
DF 19.6: Vortrag
Freitag, 20. März 2015, 10:45–11:00, C 243
High frequency laser heated AC-chip calorimeter for dynamic glass transition investigation in room temperature ionic liquids — •Evgeni Shoifet1,2,3,4, Heiko Huth1, Sergey Verevkin2,4, Christoph Schick1,4, and Egon Hassel3 — 1Institute of Physics, University of Rostock, 18057 Rostock, Germany — 2Institute of Physical Chemistry, University of Rostock, 18059 Rostock, Germany — 3Department of Technical Thermodynamics, Faculty of Mechanical Engineering and Marine Technology, Rostock, 18051 Rostock, Germany — 4Faculty of Interdisciplinary Research, Department "Life, Light and Matter", University of Rostock, Germany
Many ionic liquids are good glass formers. Nevertheless, for the relaxation behavior only a few studies of the dynamic glass transition in ionic liquids are available so far. Particularly the frequency dependence of the dynamic glass transition (α-relaxation) is not known for most ionic liquids. The standard technique for such studies - dielectric spectroscopy - is not easily applicable to ionic liquids because of the high electrical conductivity. In addition, dielectric spectroscopy is equally sensitive to the segmental relaxation (α-relaxation) and secondary relaxation but calorimetry is sensitive solely to segmental relaxation.
We try to use calorimetric techniques to obtain complex heat capacity and to investigate the dynamic glass transition of room temperature ionic liquids (RTILs) in a wide frequency range. This can give an insight in cooperative motions of ions and ion clusters in RTILs. Particularly the influence of alkyl chain length on the α-relaxation in the frequency range from 1 mHz to 0.1 MHz [Shoifet. E. et. al. (2013)].