Molecular dynamics in confining geometries

The molecular dynamics of confined (low molecular weight and polymeric) sys tems is determined by the counterbalance between surface- and confinement-e ffects: Due to the interaction with the (inner) surfaces (e.g. the formatio n of H-bonds, grafting, physisorption) the molecular dynamics is slowed dow n, resulting in an increase in the glass transition temperature of the syst em. In contrast the confinement may induce an increase in "free volume" thu s making the molecular dynamics faster than in the bulk. This causes a decr ease in the glass transition temperature. This counterbalance will be exemp lified by employing broadband dielectric spectroscopy (10(-2)Hz - 10(9)Hz) to study the molecular dynamics of the low molecular weight liquid ethylene glycol being contained in zeolites of different topology.