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dc.creatorGlushchenko, A.en_US
dc.creatorPuchkovskaya, G.en_US
dc.creatorReznikov, Yu.en_US
dc.creatorYakubov, A.en_US
dc.creatorYaroshchuk, O.en_US
dc.description1. M. Kreuzer, T. Tschudi and R. Eidenschink, Mol. Cryst. Liq. Cryst. 223, 219 (1992). 2. O. Yaroshchuk, Yu. Reznikov, A. Glyshchenko and N. Lopukhovich, Proc. 15-Th ILCC, Budapest 1, 467 (1994).en_US
dc.descriptionAuthor Institution: Natnl. Ac. Sc., Pr. Nauki 46, Kiev 252022 Ukraine.en_US
dc.description.abstractPrincipally new heterogeneous medium was recently $introduced^{1,2}$, which seems to be beneficial in systems for optical information recording, processing and/or displaying. It is a suspension of small (100-150 A) silica particles (called acrosil) in a nematic liquid crystal. Presence of these acrosil particles leads to the origin of multiple director orientation distortions leading to a high light scattering, the latter being easily controllable by electric field. Usual acrosil specific surface mounts up to 300-400 sq. m/g and its properties could be specially chemically modified This makes LC-acrosil system very attractive for scientific investigations, first of all from the point of view of the influence of surface - LC interaction. In the paper investigations of IR-spectra of such heterogeneous systems being made to the first time are presented. Usual nematic LC (5CB) was chosen with the stuff used to fill either the standard A-300 acrosil or that modified with polymethylsioxane. On the surface of the latter existing OH-groups were primarily replaced by polymethylsiloxane and it became hydrophobic. IR-spectra were obtained independently for the liquid crystal, both ordinary and modified acrosil and their mixtures in the spectral region within $400-4000 cm^{-1}$, with or without electric field application in different experimental geometry and in ordinary and polarized light. Comparison of the vibration spectral regions attributed to either phenyl rings and OH-bonds has shown that they were not the simple summation of that of the initial components. Under the application of the alternative electric field (2 kHz) light transmittance of the mixture in the IR-region appeared to increase in several times. Intensity redistribution in the phenyl-ring region of 5CB $(1400-1620 cm^{-1})$ was also observed in suspensions with ordinary and modified acrosil, what might be the result of changes either in LC-molecule conformations or intermolecular interactions. Variations of the dichroism of C=N-band and phenyl ring bands affirm the primary LC-molecule orientation along the electric field direction. Changes of the q(OH)-band dichroism in the range of $2600-3800 cm^{-1}$ were observed for the mixtures with unmodified acrocil. The data obtained could be qualitatively explained in the frames of the model of the LC-director reorientation and point out at the important role of liquid crystal molecule interaction with the acrosil system in the process. The possibility of such a system usage as a modulator of IR-radiation is also worth considering.en_US
dc.format.extent84398 bytes
dc.publisherOhio State Universityen_US

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