Homeotropic alignment of nematic liquid crystals with negative dielectric anisotropy

We report here uniform and defect-free homeotropic alignment of nematic liquid crystal having negative dielectric anisotropy (Δε<0) on cleaned substrates, which can be changed to bright state (homogeneous alignment) by applying an electric field. However, non-uniformity in the bright state would not be desirable for display devices. Therefore, silane treated and gently rubbed substrates have been utilised to obtain uniform bright state. Several textural, dielectric, and optical transmission studies have been carried out to explore the applicability of studied material in the liquid crystal display applications. Furthermore, such materials could also be useful for making colourful displays without colour filters.