Dresden 2011 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: Poster: Confinement of Polymers in Nanoscopic Layers - How Much do Properties Change?

CPP 21.3: Poster

Dienstag, 15. März 2011, 18:00–20:00, P2

Dynamic Glass Transition of Thin Poly(Bisphenol A Carbonate) Films — •Huajie Yin and Andreas Schönhals — BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin, Germany

The dynamic glass transition (α relaxation) of thin poly(bisphenol A carbonate) films (down to 10 nm) capped between two aluminum electrodes is investigated by dielectric relaxation spectroscopy. There is no thickness (polymeric layer) dependence of the dynamic glass transition temperature down to a critical thickness of 20 nm. For thickness below ~ 20 nm, an increase of dynamic glass transition temperature is observed. The Vogel-Fulcher-Tammann (VFT) equation is further applied to fit the data of relaxation rate vs dynamic glass transition temperature which reveals that the Vogel temperature increases with decreasing film thickness d. These peculiar properties are discussed in terms of the formation of a top layer of adsorbed poly(bisphenol A carbonate) segments having a reduced molecular mobility with regard to bulk poly(bisphenol A carbonate) at the experimental time scale. Contact angle measurement is performed to confirm the strong interaction between the aluminum layer and poly(bisphenol A carbonate). The interfacial energy between them is calculated to be 3.1 mJ/m2 which is related to an increase of dynamic glass transition temperature.