Berlin 2005 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 24: Polymer films II

CPP 24.2: Talk

Tuesday, March 8, 2005, 15:30–15:45, TU C130

Mechanical spectroscopy of polymer films of reduced dimensions and with different cross-linking degree — •Tatjana Haramina, Hans-Georg Brion, and Reiner Kirchheim — Institut für Materialphysik, Uni-Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen

Anelastic behaviour of a material is caused by different motions in material. The time lag between the stress and the strain, anelasticity, influences the damping of the material. This can be observed by means of mechanical spectroscopy.

Dynamics of the supported thin polymer films differs from that of the bulk polymers due to the surface contribution as well as the substrate-film interface contribution. We study the glass transition of thin polystyrene films on silicon substrates. The mechanical spectra show the shift of the glass transition temperature to lower values and broadening of the transition width, which is consistent with the idea of liquidlike layer on the surface and of an interaction between film and substrate.

Additionally the Poly(vinyl cinnamate) films on silicon substrates are studied. With an increase in the degree of cross-linking the glass transition becomes weaker and shifts to the higher temperatures. These changes in the mechanical spectra prove the decrease of the molecular mobility caused by the photo-cross-linking.