Structure/ Dielectric properties relationships in nematic liquid crystal cells/ Calixarene alignment layers interactions

Abstract

The dielectric relaxation of a nematic liquid crystal (NLC) cells, induced by several calixarene layers, has been investigated. The alignment layers were deposited onto the ITO slides using an evaporation technique and categorized using wettability technique and atomic force microscopy (AFM). These treated plates were used to prepare liquid crystal cells which induce a planar orientation of the NLC molecules. It has been shown that the calixarene alignment layers have a blocking effect on the liquid crystal cell at a high frequency. It has also been established that the dielectric relaxation is caused by the double layer formed by the adsorption of impurity ions in (NLC) molecules onto the electrode surfaces of the cells. The dielectric behavior of nematic liquid crystal cells was studied by impedance spectroscopy in frequency range, from 1mHz to 13MHz. The Nyquist diagrams are discussed in term of equivalent electrical circuit.