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Dielectric relaxation behavior of nematic liquid crystal cell using β-cyclodextrin as an alignment layer

Marwa Sahraoui, Asma Abderrahmen, Rim Mlika, Hafedh Ben Ouada, Abdelhafidh Gharbi


In the present investigation, we report the dielectric properties of a symmetric Nematic Liquid Crystal (NLC) cell using Beta Cyclodextrins (β-CD) as alignment layers. These layers were deposited onto Indium Tin Oxide (ITO) surface by thermal evaporation and then characterized using contact angle measurement. This revealed a hydrophilic character attributed to the presence of hydroxyl groups. Morphological study was carried out by Scanning Electronic Microscopy (SEM).

The dynamic impedance study of the Liquid Crystal (LC) cell in a wide frequency range from 1mHz to 13MHz was reported. It was found that the β-CD alignment layer had a blocking effect on the NLC cell at a high frequency range. We also report the relaxation mechanism of NLC cell which is modeled by an appropriate equivalent circuit in order to understand the electrical properties of the liquid crystal cell and to investigate the processes taking place at different interfaces. 

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