Regensburg 2007 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 7: POSTER: INTERNAL SYMPOSIUM Scattering Experiments
CPP 7.4: Poster
Montag, 26. März 2007, 16:00–18:00, Poster B
Dielectric and neutron spectroscopy on nano-confined liquid crystals — Stefan Frunza1, Ligia Frunza1, •Andreas Schoenhals2, Maria Mayorova3, Reiner Zorn3, and Bernhard Frick4 — 1National Institute of Materials Physics, R-76900- Bucharest-Magurele — 2Federal Institute for Materials Research and Testing (BAM), — 3Research Center Jülich, Institute for Solid State Research, D-52425 Jülich — 4Institut Max von Laue - Paul Langevin, B.P. 156, F-38042 Grenoble
The liquid crystals E7 and 8CB are confined to the nanopores of the molecular sieve Al-MCM-41 with a mean diameter of the pores of 2.5 nm. Dielectric spectroscopy shows that for the confined system one relaxation process is observed. Its characteristic relaxation time is much lower compared to that of the bulk. The temperature dependence of the relaxation time of this relaxation process shows some similarities to glassy dynamics. Moreover excess contributions to the vibrational densities of state (Boson-Peak) were found by neutron scattering using the time-of-flight spectrometer IN4 at the ILL in Grenoble. The Boson- Peak is a characteristic feature of glassy behaviour. In addition elastic scans are carried out at the backscattering spectrometer IN10 (ILL) These measurements show a signature for glass transition.