Time-varying ionic properties of a liquid-crystal cell

Abstract

This work investigates time-evolved ionic characteristics of a homogeneously aligned cell composed of a low-resistivity nematic liquid crystal. The influence of montmorillonite as a nanoadditive is studied on the dielectric spectrum of the cell. The incorporation of the inorganic nanoplatelets into the nematic leads to decrease in conductivity in the frequency range from 10 Hz to at least 10 kHz. The dielectric spectroscopic results show that the conductivity, ionic concentration, and diffusion constant of both undoped and doped cells are strongly time-dependent after the cell fabrication.

Nano-Objects and Ions in Liquid Crystals: Ion Trapping Effect and Related Phenomena

“…Typically, an octahedral m at the same concentration) in liquid crystals. It was also observed that the efficiency to trap ions by nano-clay was varying in time [213]. More efficient ion trapping in liquid crystals can be achieved by combining low concentrations of nano-clay with comparable amounts of carbon nanotubes [214].…”

“…Very interesting electrical behavior was found in liquid crystal systems doped with montmorillonite platelets [211][212][213][214][215][216][217]. Montmorillonite is a type of smectic clays characterized by a sandwich "tetrahedral-octahedral-tetrahedral" structure made of aluminosilicate lamellar materials.…”

“…Conducting nanofiber NLC Increase in the conductivity [208,209] Polymeric nanoparticles FLC Decrease in dielectric losses [210] Nanoclay (montmorillonite) NLC Ion trapping, time dependent properties, and aggregation [211][212][213][214][215][216][217] x x S ZnO …”

Investigation of liquid crystal dispersion and dielectric relaxation behavior in polymer dispersed liquid crystal composite films

“…H.H. Liu and W. Lee have studied dielectric properties of MMT doped nematic LC E7 and have found that, in the low frequency region (f b 10 Hz), the dielectric permittivity is governed by electrode polarization and space charge polarization [29]. As frequency is inversely proportional to the time, at high frequencies, molecules have less time to cope with an applied electric field.…”

Alumina nanoparticles find an application to reduce the ionic effects of ferroelectric liquid crystal

“…Lee et al [13] observed that a degraded nematic LC material could be recovered by adding complex coordination polymers via chemical adsorption. Liu et al [14] showed that inorganic montmorillonite (MMT) nano-platelets were able to suppress the ionic effect by trapping the ions. Onishi et al [15] developed a FLC display device with good display quality without the deterioration of display characteristics, as a result of trapping the ionic impurities effectively by adding an organic material which traps ions and lowers conductivity of a LC layer.…”