Dielectric properties of four room temperature ferroelectric and antiferroelectric multi-component liquid crystalline mixtures

Debnath, Asim; Mandal, Pradip

doi:10.1080/02678292.2018.1489986

Cited by 14 publications

(2 citation statements)

References 75 publications

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“…Typical domain texture was observed in SmC* phase which transformed into a uniform planar aligned texture in SmA* phase to a usual long pitch cholesteric droplets texture in N* phase before going to isotropic phase [15]. It might be mentioned here that when four fluorinated chiral dopants differing only in number and location of fluorine atoms in the molecular rigid core were doped (60 wt% of each) in the same host mixture (HM) they produced two ferroelectric and two antiferroelectric liquid crystal mixtures [16,17]. Not only that, one of the dopant at lower concentration (10 wt%) produced an electroclinic mixture with large field-induced tilt and very small layer contraction [18] and at much higher concentration (75 wt%), it formed a wide range ferroelectric mixture with a few hundred micro-second switching time [19].…”

Section: Opm and Dsc Studymentioning

confidence: 87%

Effect of non-mesogenic chiral terphenylate on the formulation of room temperature ferroelectric liquid crystal mixtures suitable for display applications

Debnath

Mandal

Sarma

et al. 2019

Journal of Molecular Liquids

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By varying the concentration of a chiral terphenylate dopant in a four-component achiral phenyl pyrimidine-based host mixture we have formulated six ferroelectric liquid crystal mixtures. Though the dopant is nonmesogenic it is observed that only 2wt% of it induces polarity in the host mixture at 32 o C. With increasing concentration, the mixtures show ferroelectric behaviour even below ambient temperature down to at least 12°C. Optical polarizing microscopy, differential scanning calorimetry, dielectric and electrooptic studies reveal that with respect to temperature range, phase sequence, spontaneous polarization, optical tilt angle and switching time the formulated mixtures are suitable for ferroelectric based liquid crystal displays.

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Section: Opm and Dsc Studymentioning

confidence: 87%

Effect of non-mesogenic chiral terphenylate on the formulation of room temperature ferroelectric liquid crystal mixtures suitable for display applications

Debnath

Mandal

Sarma

et al. 2019

Journal of Molecular Liquids

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“…The study of NLC mixtures is due to the fact that the expansion of the temperature range of the nematic phase relative to the mixture components, which is inherent in mixtures, makes it possible to study the dynamics of orientational processes in the region of states that are not affected by pretransition phenomena. This opens up the prospect of evaluating the effect of heterophase fluctuations on the kinetic properties of the mesophase [1,2]. Along with the study of the nematicisotropic phase transition, it is of interest to study the dynamics of critical phenomena in the region of the nematic-smectic liquid crystal phase transition.…”

Section: Methodsmentioning

confidence: 99%

Propagation of ultrasound near phase transitions in the liquid crystal working environment of technical devices

Larionov

Дедов²,

Mashin³

et al. 2023

E3S Web Conf.

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The results of measurements of the velocity and absorption coefficient of ultrasound in a nematic phase oriented by a magnetic field are presented. Within the framework of the hydrodynamics of the nematic phase, the coefficients of the bulk and shear viscosity of the nematic phase are calculated. The temperature dependence of the shear viscosity coefficients is exponential. The nature of the sharp increase in the bulk viscosity coefficients with an increase in the temperature of the nematic phase in the region of the phase transition nematic liquid crystal - isotropic phase is analyzed. The analysis of the temperature dependence of the ultrasound velocity in the nematic phase, carried out under the assumption of the existence of two processes responsible for the propagation of ultrasound, allowed us to identify the critical component and calculate the relaxation time of the critical contribution. In the vicinity to the phase transition, the dependence on the temperature of the relaxation time of the critical contribution increases sharply with a divergence index equal to 1.03. The relationship between the critical contribution to the absorption and the speed of ultrasound has been established. An array of data necessary for the calculation of liquid crystal technical devices has been obtained.

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Effect of fluorinated achiral chain length on structural, dielectric and electro-optic properties of two terphenyl based antiferroelectric liquid crystals

Dey¹,

Mandal

Kula

2020

Journal of Molecular Liquids

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Dielectric properties of four room temperature ferroelectric and antiferroelectric multi-component liquid crystalline mixtures

Cited by 14 publications

References 75 publications

Effect of non-mesogenic chiral terphenylate on the formulation of room temperature ferroelectric liquid crystal mixtures suitable for display applications

Effect of non-mesogenic chiral terphenylate on the formulation of room temperature ferroelectric liquid crystal mixtures suitable for display applications

Propagation of ultrasound near phase transitions in the liquid crystal working environment of technical devices

Effect of fluorinated achiral chain length on structural, dielectric and electro-optic properties of two terphenyl based antiferroelectric liquid crystals

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