Dresden 2017 – wissenschaftliches Programm
CPP 37.4: Vortrag
Mittwoch, 22. März 2017, 11:00–11:15, ZEU 255
Dynamic glass transition in the supercooled liquid and plastic crystal of ethanol — •Yeong Zen Chua1, Amanda R. Young-Gonzales2, Ranko Richert2, and Christoph Schick1 — 1Institut für Physik, Universität Rostock, Rostock, Germany — 2School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
Ethanol has been widely investigated and is well-known to exhibit a very interesting polymorphism of different solid phases: a fully-ordered (monoclinic) crystal, a (bcc) plastic crystal, a glassy plastic crystal and an ordinary amorphous glass. Physical vapor deposition (PVD) has been used to prepare amorphous glasses of ethanol, which upon heating to higher temperature transforms into the plastic crystal of ethanol. The dynamic glass transition of supercooled liquid of ethanol is successfully measured by AC nanocalorimetry. Preliminary results for the plastic crystal are also presented. With that, the frequency dependency of the dynamic glass transition of the supercooled liquid of ethanol is measured and compared with published dielectric data. Comparison of dielectric data of supercooled liquid of ethanol with AC nanocalorimetric data shows that ethanol exhibits Debye peak, which cannot be observed in AC nanocalorimetry. In previous published dielectric data, the prominent Debye peaks have been mistaken as structural α relaxation. The dielectric data have been re-evaluated and the high frequency wing in the dielectric spectra is identified as the structural α relaxation.