Investigation of applicability of nematic liquid crystals doped with disperse orange dye in guest-host systems

Liquid crystals are important materials in display technology, because they are basic components of liquid crystal displays (LCDs). The possibilities of changing orientation of liquid crystal molecules by the applied electric fields, is important for their use in LCDs. Guest-Host liquid crystal displays (GH-LCDs) have attracted much attention because of their wide viewing angle, lower costs, excellent hues and high brightness levels. The aim of this study is to improve the molecular orientation and to investigate effects on the nematic-isotropic phase transition temperature of dyes having different molecular structure. For this purpose, three different dyes (disperse orange 11, 13 and 37) were separately doped to nematic liquid crystal (ZLI-1132). Their solubilities, order parametres, textures and phase transition temperatures were determined. In conclusion, maximal solubility were assessed as 2,60% for Disperse orange 13 dye ; maximal order parameter value (S=0,56) was obtained with azo structured Disperse orange 37. Morever, doping dye into ZLI-1132 did not demonstrate negative effect on the phase transition temperature.Keywords : Nematic liquid crystal, Order parameter, Texture, Dispers dye, Guest-Host systems, Phase transition