Regensburg 2010 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 3: Poster I: Nano- and microstructured dielectrics, surfaces and interfaces, dielectric composites

DF 3.9: Poster

Montag, 22. März 2010, 15:00–17:30, Poster D1

Fatigue in ferroelectric polymers: Polyvinylidene fluoride (PVDF) — •Jörg Schütrumpf, Sergej Zhukov, and Heinz von Seggern — Technische Universität Darmstadt, Darmstadt, Deutschland

A strong piezoelectricity, pyroelectricity and ferroelectricity in polyvinylidene fluoride (PVDF) made this polymer an object of detailed studies over the last 20 years. Ferroelectric polymers have an advantage over traditional ferroelectric materials due to their good mechanical properties. Although the stability of the ferroelectric polarization in PVDF is not satisfying for a wide range of applications, it still remains a model material for numerous studies on polarization and hysteresis phenomena in ferroelectric polymers. In order to gain a more systematic understanding of the polarization properties we performed fatigue experiments on 9 µm thin uniaxial stretched PVDF films. After bipolar stressing of the samples above the coercitive field strength E_c at frequencies from 50 Hz up to 10 kHz, switching curves and hysteresis loops were investigated. By comparing fatigued with unstressed samples the underlying effects of aging and fatigue are determined. We also report on the back-switched fraction of the polarization after an applied electric field is switched off with and without fatigue. Therefore the poling times are varied over nine decades for each electric field and the back-switched part during short-circuiting is measured at the end of each poling pulse.