Electro-optic properties of nematic liquid crystal filled with monodispersed non-organic nanoparticles

摘要

The electro-optic properties of nematic liquid crystal (LC) E7 filled with non-organic monodispersed nanopaticles (MNP) are investigated. As filler we used spherical MNP of antimony pentoxide (Sb_2O_5) and silica (SiO_2) having similar size. We investigated both non-stabilized and polymer (P) stabilized LC-MNP suspensions. By variation of the component concentrations different system morphologies were obtained. It is show that insertion of MNP in LC leads to drastic increase of light scattering which can be effectively controlled by the electric field. We obtained moderate driving voltage, short response time and relatively high contrast in the samples with optimized concentration of MNP. The improved contrast and response time were also achieved in LC-P composites by doping them with MNP. In both polymer stabilized and non-stabilized composites the contrast was higher in case of Sb_2O_5 filler. It is show that particle material and geometrical size strongly influence electro-optic properties of composites. The concentration dependencies of LC-MNP-P composites can be explained assuming strong absorption of MNP by polymer during photo-induced phase separation.