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 21.2: Poster

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

Glassy dynamics of ultra-thin layers of polyisoprene — •Emmanuel Mapesa, Martin Tress, and Friedrich Kremer — Universität Leipzig, Leipzig

Broadband Dielectric Spectroscopy (BDS) - in combination with a nanostructured electrode arrangement - is used to study thin layers of polyisoprene. In the view of BDS, polyisoprene belongs to a special type of polymers because a part of its molecular dipole moment attached to each monomer unit is aligned along the main chain. These fraction adds up to one dipole moment of the whole polymer chain corresponding to the end-to-end vector of the molecule. This enables the investigation of two distinct relaxation modes taking place at two different length scales: the segmental motion which involves structures of about 1 nm in size (2 to 3 monomer units) and the so-called normal mode which represents the dynamics of the whole macromolecule. By making measurements on identical samples in capped and uncapped geometries, and systematically reducing the layer thicknesses, we show clearly the changes that occur in these two relaxation processes due to the presence of a solid interface. Special attention is given to sample preparation and treatment.