Desorption Processes of Adsorbed Impurity Ions on Alignment Layers in Nematic Liquid Crystal Cells

Abstract

The desorption processes of adsorbed impurity ions on various alignment layers in nematic liquid crystal cells have been studied by measuring ac conductivity of the cells. The liquid crystal used here is 4-cyano-4′-pentyl biphenyl. The adsorption of the ions is induced by the application of dc voltage to the cells. It is found in all alignment layers that the adsorbed ions decay exponentially after the cessation of the. dc voltage application, and that the time constants of the decay exhibit thermally activated behavior. It is shown that the desorption process is governed by the surface energy of the alignment layers.