Electro-Optical and Photo Stabilization Study of Nematic Ternary Mixture

Abstract

Liquid crystal materials composed of mixed nematic compounds find broad use in liquid crystal displays and photonic applications. A ternary mixture formed from three different nematic compounds shows peculiar behavior such as tunable electro-optical properties dependent on the frequency of the driving voltage. The paper presents an analysis of the response time and phase retardation of a frequency tunable nematic liquid crystal mixture (under code name 5005). This material possesses high birefringence (Δn = 0.32 at 633 nm) as well as high dielectric anisotropy (Δε = 6.3 at 100 Hz). The unique property of the 5005 mixture is frequency-controlled phase modulation, as in a dual frequency liquid crystal, while dielectric anisotropy goes to zero instead of being negative at high frequencies. For each component of the mixture, details on mesomorphic properties and their role in the formulation of the mixture are reported. The 5005 mixture was characterized by multiple investigation techniques, such as temperature dependence dielectric anisotropy, transmittance measurements image polarizing microscopy, and UV stability.

A high birefringence liquid crystal for lenses with large aperture

“…Structures belong to fluorine substituted alkyl-alkyl phenyl-tolanes, alkyl-alkyl bistolanes and fluorine substituted 4-[(4-cyanophenoxy)carbonyl]phenyl 4-alkylbenzoates. This material possesses high birefringence ( n = 0.32) as well as high dielectric anisotropy ( = 6.3), with the unique property of frequency-controlled phase modulation, as in a dual-frequency liquid crystal, with the difference that its dielectric anisotropy goes to zero instead of being negative at high frequencies 24 .…”

Binary Nematic Liquid Crystals Mixture with Enhanced Electro-Optics Properties for Photonic Applications

“…The pure NLC materials compared to other LC materials are of relatively lower cost. Thus, by mixing different NLCs, best switching properties with affordable cost can be attained [6][7][8][9][10][11][12]. Nowadays it is of great interest to design new NLCs or to find new miscible binary mixtures of NLCs of low cost, low viscosity, modest dielectric anisotropy, proper elastic constants, high thermal stability for long-term operation, positive birefringence, and high Nematic to Isotropic transition temperatures (TNI) much higher than room temperature [13].…”