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DF: Dielektrische Festkörper

DF 3: FV-internes Symposium „Polare Polymere und Ferroelektrete“

DF 3.1: Hauptvortrag

Samstag, 5. März 2005, 08:30–09:10, TU C130

Polymer ferroelectrics and ferroelectrets — •Reimund Gerhard-Multhaupt — Department of Physics, University of Potsdam, Am Neuen Palais 10, D-14469 Potsdam

The orientation of molecular dipoles in the polymer chains and their stabilisation within crystalline domains by means of structural features and/or electrical charges render several semicrystalline polymers ferroelectric. Recent research shed new light on copolymers of polyvinylidene fluoride (PVDF), on odd-numbered polyamides and on polymeric relaxor ferroelectrics obtained through irradiation or copolymerisation. In addition, voided space-charge electret polymers have been shown to exhibit ferroelectric-like behavior and are thus often called “ferroelectrets” [1]. In this review, some recent developments will be reported and discussed with respect to fundamental mechanisms of ferroic behavior in polar or voided polymer electrets and to applications-relevant properties such as pyro- and piezoelectricity. It will be emphasized that polymer ferroelectrics and ferroelectrets usually contain at least two phases and are thus closely related to the well-known ferroelectric oxide-polymer micro- or nanocomposites.

[1] S. Bauer, R. Gerhard-Multhaupt, G. M. Sessler, “Ferroelectrets: Soft Electroactive Foams for Transducers”, Physics Today 57(2), 37–43 (February 2004).