Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 41: Glasses and Glass Transition II (jointly with DY, DF)
CPP 41.4: Vortrag
Donnerstag, 17. März 2011, 11:45–12:00, ZEU 114
Dynamics of glass forming liquids in soft confinement — •Emmanuel Gouirand1, Thomas Blochowicz1, Andreas Blank1, Bernd Stühn1, and Bernhard Frick2 — 1Institut für Festkörperphysik, TU Darmstadt — 2Institut Laue-Langevin, Grenoble, France
In search of a characteristic length scale associated with cooperative dynamics at the glass transition, intensive effort has been devoted to investigating the influence of confinement on the dynamics of glass forming
liquids. Nevertheless, no generally accepted picture exists so far because of the complex interplay of surface, pressure and finite size effects affecting the dynamics.
We investigate the dynamics in confinements of different nature in order to be able to disentangle these various effects. Therefore, we apply photon correlation spectroscopy and quasi elastic neutron scattering on glass formers confined within microemulsion droplets, the structure of which proved to remain stable over the whole temperature range by means of small angle scattering.
First, we report on the dynamics of glycerol confined in AOT micelles where the glass transition temperature (Tg) of the matrix is chosen to be smaller than Tg of the glycerol core (fast soft confinement). We find glycerol to relax faster than in bulk with an Arrhenius temperature dependence [1].
Then we compare the dynamics of toluene in Cremophor ELP micelles. Contrary to the former situation, here the matrix relaxes slower than the core and slows down the latter due to interfacial effects. Finally, below Tg of the matrix actual hard confinement of toluene within the droplets is realized.
Blochowicz et al., CPL 475, 171-174 (2009)