Dresden 2003 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 1: Polymerschmelzen
CPP 1.4: Vortrag
Montag, 24. März 2003, 10:45–11:00, ZEU/160
Structure and mechnical properties of smectic liquid crystalline elastomer films — •Ralf Stannarius1, Ralf Köhler1, Christian Tolksdorf2, and Rudolf Zentel2 — 1Universität Leipzig, Inst. für Experimentelle Physik I, Linnéstr. 5, 04103 Leipzig — 2Universität Mainz, Inst. für Organische Chemie, Duesbergweg 10-14, D-55099 Mainz
Smectic liquid crystalline elastomers (LCE) combine in a unique way the elasticity conventional rubbers with anisotropic properties of liquid crystals, they can be ferro- and piezoelectric, and open perspectives for application as sensor and actuator materials. Macroscopically oriented LCE films can be produced by UV-irradiation of free standing films of photo-crosslinkable polymeric smectogens.
Optical microscopy, small angle x-ray diffraction and atomic force
microscopy
are employed for structure characterization. Smectic LCE balloons and thin
planar
films are mechanically stretched to determine their elastic properties
[1,2].
in the different mesophases.
The network topology determines the coupling of mechanical
behaviour and microscopic orientation.
Within elastic models we consider contributions of entropy elasticity and
smectic layer compression and derive elastic coefficients from
the experimental data.
In the tilted smectic C∗ phase, deviations from standard
behaviour indicate a ’soft elastic’ response of some elastomers,
which arises from a coupling between the network and the mesogen
orientation in these materials [2].
1.)
H. Schüring, R. Stannarius, C. Tolksdorf, R. Zentel,
Macromolecules 34, 3962 (2001).
2.)
R. Stannarius et al. Phys. Rev. E 65, 041707 (2002).