Authors Tress, M. ; Erber, M. ; Mapesa, E. U. ; Huth, M. ; Müller, J. ; Serghei, A. ; Schick, C. ; Eichhorn, K.-J. ; Voit, B. ; Kremer, F.
Title Glassy dynamics and glass transition in nanom,etric thin layers of polystyrene
Date 13.12.2010
Number 26283
Abstract Broadband dielectric spectroscopy (BDS), spectroscopic vis-ellipsometry (SE), X-ray reflectometry (XRR), and alternating current (ACC) as well as differential scanning calorimetry (DSC) are combined to study glassy dynamics and the glass transition in nanometric thin (=5 nm) layers of polystyrene (PS) having widely varying molecular weights (27500-8090000 g/mol). For the dielectric measurements two sample geometries are employed, the common technique using evaporated electrodes and a recently developed approach taking advantage of nanostructures as spacers. All applied methods deliver the concurring result that deviations from glassy dynamics and from the glass transition of the bulk do not exceed margins of ±3 K independent of the layer thickness and the molecular weight of the polymer under study. Our findings are discussed in the context of the highly controversial literature and prove that an appropriate sample preparation is of paramount importance.
Publisher Macromolecules
Citation Macromolecules 43 (2010) 9937-9944
Tags ultrathin polymer-films ac-chip calorimeter molecular-weight temperature-dependence length scale surface relaxation interface liquids viscosity

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