International Workshop on Dynamics in Confinement

J. Phys. IV France 10 (2000) Pr7-59-Pr7-65
DOI: 10.1051/jp4:2000711

Molecular dynamics in confining geometries

A. Huwe¹, F. Kremer¹, L. Hartmann¹, Th. Kratzmüller², H.G. Braun², J. Kärger¹, P. Behrens³, W. Schwieger⁴, G. Ihlein⁵, Ö. Weiß⁵ and F. Schüth<sup>5

1</sup>  University of Leipzig, Department of Physics, 04103 Leipzig, Germany
²  Institute of Polymer Research, 01069 Dresden, Germany
³  University of Hannover, Department of Chemistry, 30167 Hannover, Germany
⁴  University Erlangen-Nürnberg, Department for Chemical Engineering, 91058 Erlangen, Germany
⁵  Max Planck Institute of Coal Research, 45470 Mülheim/Ruhr, Germany

Abstract
The molecular dynamics of confined (low molecular weight and polymeric) systems is determined by the counterbalance between surface- and confinement-effects : Due to the interaction with the (inner) surfaces (e.g. the formation of H-bonds, grafting, physisorption) the molecular dynamics is slowed down, resulting in an increase in the glass transition temperature of the system. In contrast the confinement may induce an increase in "free volume'' thus making the molecular dynamics faster than in the bulk. This causes a decrease in the glass transition temperature. This counterbalance will be exemplified by employing broadband dielectric spectroscopy (10^-2Hz - 10⁹Hz) to study the molecular dynamics of the low molecular weight liquid ethylene glycol being contained in zeolites of different topology.

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