Authors
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Serghei, A. ; Mikhailova, Y. ; Eichhorn, K.-J. ; Voit, B. ; Kremer, F.
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Title
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Discrepancies in the Characterization of the Glass Transition in Thin Films of hyperbranched polyesters
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Date
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04.10.2006
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Number
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13841
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Abstract
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The dynamic glass transition and the dilatometric glass transition temperature are simultaneously characterized in thin films of hyperbranched aromatic polyesters by broadband dielectric spectroscopy and capacitive scanning dilatometry. A diverging thickness dependence is detected: while the temperature position of the alpha relaxation peak T decreases by 30 K, the dilatometric Tg increases by 10 K with decreasing film thickness. This emphasizes the subtle character of the glass transition phenomenon - as manifested in the molecular dynamics and in the (structural) thermal expansion - and proves that, in contrast to the bulk, different experimental techniques do not necessarily deliver similar results in confinement.
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Publisher
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Journal of Polymer Science: Part B: Polymer Physics
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Wikidata
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Citation
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Journal of Polymer Science: Part B: Polymer Physics 44 (2006) 3006-3010
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DOI
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https://doi.org/10.1002/polb.20929
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Tags
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glass transition molecular dynamics thin films ultrathin polymer-films molecular-dynamics poly(methyl methacrylate) dielectric relaxations temperature polystyrene scale
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