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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 51: Poster Session III-2
CPP 51.5: Poster
Dienstag, 17. März 2020, 14:00–16:00, P2/EG
Molecular dynamics and ionic conductivity of crown ether based discotics — Arda Yildirim1, •Mohamed Aejaz Kolmangadi1, Sabine Laschat2, and Andreas Schönhals1 — 1Bundesanstalt für Materialforschung und prüfung, Unter den Eichen 87, 12205 Berlin, Germany — 2Institut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
In present study, the molecular dynamics of asymmetric crown ether based discotics (KAL) bearing alkyl chains of different lengths were investigated by Broadband Dielectric Spectroscopy (BDS). Three dielectrically active relaxation processes were observed for both materials. At low temperatures, a γ-process in the Cry state was detected and is assigned to the localized fluctuations taking place in the alkyl chains. The α1-process takes place at higher temperatures in the Cry phase. An α3 process was found in the Colh mesophase. The temperature dependence of the relaxation rates of the α3 process is a completely different than that of the α1 relaxation. Molecular assignments of these different glassy dynamics are proposed. Tgthermal determined by DSC agrees with the dielectric data corresponding to the detected glassy dynamics. In addition, the conductivity contribution of both KAL compounds was analyzed. The conductivity contribution appears in both Cry and Colh phases at temperatures above 300 K.