Berlin 2005 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 29: POSTER: Polymer physics
CPP 29.5: Poster
Tuesday, March 8, 2005, 16:30–18:30, Poster TU D
Strain induced compression of smectic layers in free-standing liquid crystal elastomer films — •Victor Aksenov1, Jürgen Bläsing1, Martin Rössle2, Ralf Stannarius1, and Rudolf Zentel2 — 1Univesity Magdeburg, Institute of Experimental Physics — 2University of Mainz, Institute of Organic Chemistry
Liquid crystal elastomers (LCEs) combine rubber elasticity and anisotropic liquid crystal properties. Conventional rubber materials are isotropic and have a Poisson ratio equal to 1/2. If the stress of smectic A LCEs is in the smectic layer plane, a Poisson ratio close to 1 has been observed parallel to the smectic layer, and zero perpendicular to it [1].
The smectic LCE investigated here behaves as a conventional rubber. Optical reflectometry shows that stretching of the free standing films with smectic layers parallel to the film surface causes the change of the optical thickness of the film. Small angle X-ray scattering measurements confirm that strain leads to smectic layer compression. The measured Poisson ratio is close to 1/2.
[1] E. Nishikawa and H. Finkelmann, Macromol. Chem. Phys. 200, 312 (1999).