Regensburg 2002 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 15: Poster: Dünne Filme, Monolagen und Oberfl
ächen
CPP 15.11: Poster
Mittwoch, 13. März 2002, 16:30–18:00, B
On the dynamics of surface layer in octylcyanobiphenyl-aerosil nanocomposites — •Stefan Frunza1, Ligia Frunza1, Harald Goering2, and Andreas Schoenhals2 — 1National Institute of Materials Physics, PO Box Mg07, R-76900 Bucharest-Magurele, Romania — 2Federal Institute of Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin, Germany
A broadband dielectric study of the dispersions of silica spheres (Aerosil 380) in octylcyanobiphenyl (8CB) with densities between 0.083 and 10 g of silica per 1 cm3 of liquid crystal (LC) is reported. High values of silica densities were thus achieved for the first time to observe the behaviour of the LC monolayer on the surface of the silica particles. The relaxation characteristic of the bulk LC is noticed especially for the samples with low silica densities. Additionally, a slow relaxation was detected, even at temperatures for which the bulk LC is in the crystalline state. It was assigned to the surface layer of LC molecules. Remarkably, the temperature dependence of the relaxation rates for this slow process shows a behaviour typical for glass forming liquids.