Space charge polarization by ions in a liquid crystal material

The complex dielectric constant of a liquid crystal material, 4-cyano-4'-al kyl-biphsnyl (5CB), in a low frequency region was measured by taking the th ickness of a specimen as parameter. The results were analyzed by introducin g an equivalent circuit of a novel concept by taking two kinds of contribut ions into account: one is from the electric double layer and the other is f rom the space charge polarization. It was found that these two effects can be distinguished by observing the dependence of dielectric dispersion on th e thickness of a specimen. These measurements can be applied to a precise d etermination of the attributes of plural kinds of ions like the diffusion c oefficient and the number density.