Leipzig 1999 – wissenschaftliches Programm
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PO: Polymerphysik
PO 7: Poster: Polymere Netzwerke
PO 7.8: Poster
Dienstag, 2. März 1999, 14:00–16:00, Foyer
Atomic force microscopic studies on thin oriented films of ferroelectric liquid crystalline elastomers with varying network architecture — •Hanna Brodowsky1, F Kremer1, Elisabeth Gebhard2, and Rudolf Zentel2 — 1Physik anisotroper Fluide, Universität Leipzig, D-04103 Leipzig — 2Fachbereich Chemie, BUGH Wuppertal, D-42079 Wuppertal
Crosslinked ferroelectric liquid crystalline polymers are studied by atomic force microscopy. Polysiloxane copolymers have been synthesized with mesogenic and photo-crosslinkable side groups, the latter connected either directly to the backbone via a short spacer, or as terminal group on a part of the mesogens. These elastomers are prepared as thin freely suspended films in homeotropic orientation. Topographic measurements depict plateaus separated by steps of characteristic height, corresponding to the surfaces and edges of smectic layers. From the temperature behavior [1] as well as from the reaction to mechanical deformation [2], a model for the network architectures is proposed: In the first case (“intra-layer crosslinking“), a predominantly two dimensional network is formed within the backbone layers separating the smectic layers, in the second case (“inter-layer crosslinking“) a three dimensional network is established which is dependent on the mesophase of crosslinking.
[1] Brodowsky, H.M., et al. Langmuir 13 (1997) 5378
[2] Brodowsky, H.M., et al. Langmuir in press 1998