Regensburg 2013 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 8: Poster I: Glasses and Glass Transition (joint session DY/DF/CPP)
DY 8.1: Poster
Montag, 11. März 2013, 17:30–19:30, Poster C
Room temperature ionic liquid's (RTILs) dynamic glass transition by calorimetric methods. — •Evgeni Shoifet1,2, Heiko Huth1, Sergey Verevkin2, and Christoph Schick1 — 1Institute of Physics, Rostock University, Rostock, 18051, Germany — 2Institute of Chemistry, University of Rostock, 18051 Rostock, Germany
Many of the ionic liquids are good glass formers. Nevertheless, only a few studies of the 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. 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. The techniques that were used are DSC, TMDSC, and AC-chip calorimeter[5] covering a frequency range from 0.001 Hz to10000 Hz. Similar fragility was found not only in series of RTILs with different alkyl chain length in the cataion ([Cnmim]), but also for two different anions ([Co(NCS)2],[NTf2]). Also the decrease in thermal glass transition temperature (Tg) and add/even effect have been observed in cobalt RTIL, while the Tg in RTIL with sulfonic anion is increasing, with increase of alkyl chain length.