Changes in the electro-optical behaviour of ferroelectric liquid crystal mixture via silica nanoparticles doping

We investigated the dynamic properties of a ferroelectric liquid crystal mixture doped with silica nanoparticles using polarization current reversal method. The effect of temperature and bias field on the switching responses of silica-ferroelectric liquid crystal composites with different silica concentrations (0.01, 0.02, 0.05 and 0.1 wt%) were studied and compared. Various electro-optic properties of ferroelectric liquid crystal mixture changed according to silica nanoparticles concentration. We observed about 14% decrease in spontaneous polarization and up to 17% increase in switching response for 0.01 wt% silica dispersion, whereas a minor increase in the isotropic temperature of composites. The rotational viscosity and optical contrast increased with increasing silica concentration. At a 0.1 wt% silica nanoparticle doping concentration, the ferroelectric liquid crystal cell showed the best electro-optic properties, such as low threshold and driving voltage, better optical contrast and low tilt angle. Our experimental results show that silica doped ferroelectric liquid crystal composites are promising materials for better optical contrast in electro-optical applications. (c) 2012 Elsevier B.V. All rights reserved.