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CPP: Chemische Physik und Polymerphysik
CPP 5: Elektronische Eigenschaften von Polymeren
CPP 5.2: Talk
Monday, March 24, 2003, 17:15–17:30, ZEU/160
Separation of ferroelectric and non-ferroelectric contributions to piezo- and pyroelectricity in polyamide 11 — •Alexander Kremmer1, Peter Frübing1, Werner Neumann1, Ian Leslie Guy2, and Reimund Gerhard-Multhaupt1 — 1Department of Physics, University of Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany — 2Department of Physics, Macquarie University Sydney, NSW 2109, Australia
Ferroelectric polyamide-11 films were prepared by melting powder in a hot press at 210 ∘C, quenching in ice-water, drawing with a ratio of 3:1 at room temperature and subsequent electrical poling up to 200 MV/m in direct contact at room temperature. Ferroelectricity was checked by dielectric-hysteresis measurements. A remanent polarisation of up to 35 mC/m2 and a coercive field of 75 MV/m were obtained. The piezoelectric d33 coefficient was determined from thickness-extension resonances in the dielectric spectrum as well as by interferometrical measurements. The pyroelectric coefficient was determined from quasistatic pyroelectrical measurements. Values of 3 pC/N and 8 µC/(m2K), respectively, were obtained after annealing the poled sample close below the melting region. They are thermally stable up to 170 ∘C. Though the poling was performed below glass transition there are significant contributions of non-ferroelectric dipoles and charge carriers to the total polarisation which were separated with dielectric spectroscopy and thermally stimulated depolarisation.