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PO: Polymerphysik

PO 11: Poster: LC-Polymere und Ferroelektrizität

PO 11.8: Poster

Wednesday, March 11, 1998, 15:25–17:15, P1

Structure and Dynamics in Ferroelectric Liquid Crystalline Elastomers — •Hanna Brodowsky¹ and Friedrich Kremer² — ¹Physik anisotroper Fluide, Universit"at Leipzig, Linnestr.5, D-04103 Leipzig — ²Physik anisotroper Fluide, Universit"at Leipzig, Linnestr.5, D-04103 Leipzig

Crosslinked ferroelectric liquid crystalline polymers (FLCPs) are studied: A diluted side chain polysiloxane is varied on the molecular scale by adding a cross-linkable group either connected to the backbone via a short spacer, or placed as terminal group on the mesogens. These elastomers are compared with non-crosslinked polymers.

By combining methods to study the structure (temperature dependent AFM on thin films in homeotropic orientation, before and after applying mechanical stress, i.e. elongation within the layer plane) and the dynamics (dielectric spectroscopy, electro-optic ferroelectric switching experiments), the influence of the different types of crosslinking may be fully characterized:

In the first case ("intra-layer crosslinking"), a predominantly two dimensional network is formed within the backbone layers separating the smectic layers, restricting the mesogen movement only little. In the second case ("inter-layer crosslinking") a three dimensional network is established, imposing an elastic potential for the mesogens and thereby modifying the ferroelectric switching behavior.