Berlin 2015 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 19: Glasses and Glass Transition II (CPP with DF/DY)

DF 19.3: Vortrag

Freitag, 20. März 2015, 10:00–10:15, C 243

Dielectric spectroscopy on glycerol and water confined in metal-organic frameworks — •Jonas Fischer¹, Pit Sippel¹, Peter Lunkenheimer¹, Dmytro Denysenko², Dirk Volkmer², and Alois Loidl¹ — ¹Experimental Physics V, University of Augsburg, Germany — ²Chair of Solid State and Material Chemistry, University of Augsburg, Germany

Approaching the glass transition, the slowing down of molecular dynamics generally proceeds much stronger than expected for thermally activated motions. This can be ascribed to a temperature-dependent activation energy arising from the cooperative motion of increasing numbers of molecules at low temperatures [1]. The number of correlated molecules can be controlled by confining the glass-forming liquid in small pores. Previously, glass formers have been confined in porous glasses, zeolites and other silicates [2]. Recently, metal-organic frameworks (MOFs) have become available. This class of porous coordination polymers consists of metal-containing units and organic linkers. MOFs are tunable in many regards [3], thus allowing confinement in pores of different inner surfaces and varying sizes. Here, we present broadband dielectric spectroscopy data of glycerol and water confined in different MOFs, of the MFU-type [4]. It is shown that MOFs are well-suited for the measurement of confined liquids.
T. Bauer et al., Phys. Rev. Lett. 111, 225702 (2013).
A. Huwe et al., Phys. Rev. Lett. 82, 2338-2341 (1999).
H. Furukawa et al., Science 341, 1230444 (2013).
D. Denysenko et al., Chem Commun. 48, 1236 (2012).