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CPP: Chemische Physik und Polymerphysik

CPP 24: Polymer films II

CPP 24.1: Vortrag

Dienstag, 8. März 2005, 15:15–15:30, TU C130

Calorimetric Glass Transition in Polystyrene Films of Nanometer Thickness — •Heiko Huth, Alexander Minakov, and Christoph Schick — Universität Rostock, Institut für Physik, Universitätsplatz 3, Rostock 18051

We investigated a series of thin polystyrene films in the range of 50 nm down to 4 nm. The films are produced by spin coating. The thickness was measured by capacitance measurements using films produced under the same conditions. The AC-calorimetric investigations were done by a new calorimeter, which has the sensitivity to measure samples below one nanogram or heat capacities below 1 nJ/K, respectively. A detailed description of the method is given in another paper. The calorimetric measurements were done under the same condition for all samples of the series. The second heating and cooling curve obtained at 40 Hz and 2 K/min was used. We do not find any influence of film thickness on the glass transition temperature down to 4 nm. There are only changes in curve shape for the thinnest films. This shows that we really measure thin films and not droplets of the sample due to dewetting.