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Dynamics of Ferroelectric and Nematic Liquid Crystals Confined in Porous Matrices

Published online by Cambridge University Press:  15 February 2011

Fouad M. Aliev
Fouad M. Aliev*
Affiliation:
Department of Physics and Materials Research Center, PO BOX 23343, University of Puerto Rico, San Juan, PR 00931-3343, USA
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Abstract

We performed dielectric spectroscopy measurements to study dynamics of collective modes of ferroelectric (FLC) and molecular motion of nematic (NLC) liquid crystals with polar molecules confined in silica macroporous and microporous glasses with average pore sizes of 1000 Å (volume fraction of pores 40%) and 100 Å (27%) respectively. For FLC the Goldstone and the soft modes are found in macropores. The rotational viscosity associated with the soft mode is about 10 times higher in pores than in the bulk. These modes are not detected in micropores although low frequency relaxation is present. The last one probably is not connected with the nature of liquid crystal but is associated with surface polarization effects typical for two component heterogeneous media. The difference between the dynamics of orientational motion of the polar molecules of NLC in confined geometries and in the bulk is qualitatively determined by the total energy Fs of the interaction between molecules and the surface of the pore wall, which is found Fs ≈ 102erg/cm2.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 366: Symposium N – Dynamics in Small Confining Systems , 1994 , 445
Copyright
Copyright © Materials Research Society 1995

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