Relationship between Molecular Structure and Temperature Dependence of Threshold Voltage in Fluorinated Liquid Crystals

Abstract

We evaluate the temperature dependence of threshold voltage and physical constants (anisotropy of dielectric constants and elastic constants) by using fluorinated phenylbicyclohexane liquid crystal compounds. It is found that the positions of fluorine substituents influence the dielectric constant and its temperature dependence. A systematic relationship between the fluorine substituents and physical constants was obtained.

Relationship between order parameter and physical constants in fluorinated liquid crystals

“…The dielectric constants of phenylbicyclohexane ( PBC) compounds with one or two¯uorine substituents in the benzene ring Table 1. [1 ]. In this paper, we present the relationship between the order parameter and the physical constants of Transition dielectric anisotropy and splay elastic behaviour for the Temp constant parallel to the molecular long axis e d was the same value below the dye concentration of 0´5 wt % and are in good agreement with those reported by Karat calculated from an extrapolation in capacitance as a function of the inverse voltage characteristics, i.e.…”

Study of the molecular configuration and the dipole moment in fluorinated liquid crystals

“…In particular, the materials exhibit great divergence in dielectric constant [5,6,20]. On the other hand, the molecular hydroxyl link has little effect on the physical properties.…”

“…Therefore, the search for applications for fluorinated LC materials has intensified. Nishi et al [5] and Ma et al [6] evaluated the temperature dependence of threshold voltage and physical constants (anisotropy of dielectric constants and elastic constants) of fluorinated PBC with one or two fluorine substituents in various positions of the benzene ring. They found that the positions of fluorine substituents influence the dielectric constant and its temperature.…”

“…However, it is found there has been no quantitative study of the relationship between the substitute fluorine atoms, positions and electrophysical properties. Therefore, the study is necessary and meaningful after the experimental research [5][6][7], such as, relationship between order parameter and physical constants in fluorinated LC.…”

3-Aryl- or 3-(trans-4-alkylcyclohexyl)- 6-arylcyclohex-2-enones: synthesis, transformations and mesomorphic properties

“…In this paper we describe continued investigations of 3,6-disubstitute d cyclohex-2-The liquid crystalline derivatives of quaterphenyl and terphenyl, cyclohexylbenzene and trans,trans-dicycloenones and show how these compounds can be used for the synthesis of both well known and new liquid crystalhexylbenzene are very useful in LC mixtures because they have low melting points and wide temperature ranges line derivatives of trans,trans-dicyclohexylbenzene, transcyclohexylcyclohexenylbenzene , terphenyl and quaterof their smectic or nematic phases, low viscosity and an optical anisotropy which increases from the derivatives phenyl containing uoro or chloro substituents in lateral positions. of cyclohexylbenzene (Dn~0.1) to the derivatives of quaterphenyl (Dn~0.25), allowing one to prepare LC compositions for diOE erent kinds of LC Displays [1][2][3].…”