Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 34: POSTERS Polymerphysics

CPP 34.29: Poster

Donnerstag, 28. Februar 2008, 17:00–19:30, Poster A

Molecular dynamics of ultrathin supported polysulfone films studied by dielectric spectroscopy — Diana Labahn and •Andreas Schönhals — Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin

Broadband dielectric spectroscopy (10 mHz to 10 MHz) was employed to study the glassy dynamics of ultra thin supported polysulfone layers. The ultra thin films were prepared between two aluminum electrodes. Glass slides, cleaned in an ultrasound alkaline bath, rinsed in pure chloroform, and dried under nitrogen flow, were used as supporting substrates. Thin polymer films were spin-coated from a chloroform solution at 3000 rpm. The film thickness from microns down to below 10 nm was adjusted by changing the concentration of the polymer in solution. After spin-coating, the samples were annealed at a temperature well above the bulk glass transition. As a main result, for carefully annealed samples no change of the glass transition temperature with the decreasing film thickness is observed in contradiction to literature results. A more detailed analysis using a derivative technique shows that the Vogel temperature increases und the fragility parameter decreases with decreasing film thickness.