Bayreuth 1998 – scientific programme
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PO: Polymerphysik
PO 11: Poster: LC-Polymere und Ferroelektrizität
PO 11.6: Poster
Wednesday, March 11, 1998, 15:25–17:15, P1
The direct and inverse electromechanical effect in ferroelectric liquid crystalline elastomers (FLCE) — •Walter Lehmann1, Lutz Hartmann1, Friedrich Kremer1, Peter Stein2, Heino Finkelmann2, and Kent Skarp3 — 1Universität Leipzig, Fak. f. Physik, Abt. PAF, Linnestr.5, D-04103 Leipzig — 2Universität Freiburg, Inst f. Makromol. Chemie, Sonnenstr. 5, D-79104 Freiburg — 3Dep. of Physics, Chalmers University of Technology, S-41296 Göteborg, Sweden
Dynamical measurements of the direct and inverse electromechanical response (i. e. the coupling to mechanical stress and to electric fields) in a ferroelectric (SC*) liquid crystalline elastomer have been performed. The sample is a LC single crystal in bookshelf geometry that has been uniformly aligned on a macroscopic lengthscale by mechanical stress during the crosslinking. Superposition of electrical DC-bias fields during the measurements reveal the polar axis of the sample and the phase transition ferroelectric to paraelectric. Additional rheological and X-ray measurements show evidence for a molecular motion model based on the movement of inclined smectic layers. To study the role of the electroclinic effect in the piezoelectric response interferometric measurements on polymeric LC-films in homeotropic orientation are in progress.