Electro-optical properties of a new series of fluorinated antiferroelectric orthoconic liquid crystalline esters

Pramanik, Anamika; Das, Malay Kumar; Das, Bidisa; Żurowska, M.; Dąbrowski, R.

doi:10.1080/02678292.2014.996792

Cited by 40 publications

(11 citation statements)

References 46 publications

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“…The current response was recorded by a digital storage oscilloscope (1052A), suitably interfaced with a computer, the detailed method of which is given in Ref. [ 67 ]. The relaxation time, τ, rotational viscosity, η, and the anchoring coefficients W p and W d were evaluated for all the mixtures, by a method, the description of which has been given by us in our earlier publications [ 67 ].…”

Section: Methodsmentioning

confidence: 99%

“…[ 67 ]. The relaxation time, τ, rotational viscosity, η, and the anchoring coefficients W p and W d were evaluated for all the mixtures, by a method, the description of which has been given by us in our earlier publications [ 67 ]. Static dielectric measurement was performed using a digital LCR-bridge (Agilent E4980A); the permittivity parallel and perpendicular to the molecular long axis, ε || and ε ⊥ , respectively, and hence the dielectric anisotropy (Δε = ε || − ε ⊥ ) were estimated by measuring the capacitance of a liquid crystal cell.…”

Section: Methodsmentioning

confidence: 99%

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Static Permittivity and Electro-Optical Properties of Bi-Component Orthoconic Antiferroelectric Liquid Crystalline Mixtures Targeted for Polymer Stabilized Sensing Systems

Nepal¹,

Das²,

Das

et al. 2022

Polymers

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The behavior of two newly formulated bi-component orthoconic antiferroelectric liquid crystalline (OAFLC) systems, i.e., the Compound A + Compound B mixture system and Compound C + Compound B mixture system has been discussed in light of temperature and concentration dependencies of helical pitch length, spontaneous polarization, relaxation time, bulk viscosity, and the anchoring energy strength coefficient, together with static dielectric permittivity (ε) and dielectric anisotropy. Compound A + Compound B mixtures possess spontaneous polarization between 190–340 nC.cm−2 and fast relaxation times between 190–320 µs in the smectic antiferroelectric SmCA* phase at room temperature. Compound C + Compound B mixtures also have a spontaneous polarization in the range of 190–280 nC.cm−2 and relaxation times in the range of 190–230 µs at room temperature. Most of the mixtures have a helical pitch below one micrometer in the SmCA* phase. These advanced mixtures show a broad temperature range of the antiferroelectric SmCA* phase, fast switching of molecules under an applied electric field, negative dielectric anisotropy and a short helical pitch, confirming the advantage of designing new polymer-stabilized OAFLC that is targeted for novel application in sensing devices, utilizing the fast responsive electro-optical modulation elements.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Static Permittivity and Electro-Optical Properties of Bi-Component Orthoconic Antiferroelectric Liquid Crystalline Mixtures Targeted for Polymer Stabilized Sensing Systems

Nepal¹,

Das²,

Das

et al. 2022

Polymers

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“…The mesomorphic properties of some analogues of (S)-MHPOBC (S-4-(1methylheptyloxy)carbonylphenyl4'-octyloxy-4-biphenylcarboxylate) have been studied extensively by the electro-optical method and described in details in the previous work, reported A c c e p t e d M a n u s c r i p t 4 by us [15]. Some of the investigated compounds with large spontaneous polarization and low relaxation time seem to be interesting for mixture formulation for application in surface stabilized orthoconic antiferroelectric liquid crystal (SSOAFLC) displays.…”

Section: Methodsmentioning

confidence: 99%

Preparation and Study of the Electro-optical Properties of Binary Mixtures of Orthoconic Anti-ferroelectric Esters and Achiral Phenyl Pyrimidine Liquid Crystal

Pramanik

Das

Das³

et al. 2015

Soft Materials

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We have prepared three different binary systems by mixing an achiral low viscous phenyl pyrimidine liquid crystalline SmC compound with three different orthoconic anti-ferroelectric analogous of (S)MHPOBC exhibiting SmA*-SmC*-SmC A * phase sequence. In these binary mixtures ferroelectric and antiferroelectric phases were induced and their mesomorphic parameters (spontaneous polarization, response time, effective torsional viscosity and anchoring energy coefficient) were determined by thermo-microscopic and electro-optical study. All the physical parameters show a non-additive behaviour with respect to the concentration of chiral mesogens due to strong dipole-dipole and/or intermolecular interactions between polar fluorinated chiral esters with heterocyclic phenyl pyrimidine compound. Interestingly the achiral mesogen reduces the response time of these binary mixtures at the cost of lower P s . Therefore these mixtures can be useful for high speed technological applications where low polarization, long pitch and very fast switching ferro or anti-ferroelectric liquid crystal mixtures are desirable.

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“…Liquid crystals (LCs) of low melting temperatures are important materials for a wide range of applications, including temperature sensors and electro-optical displays [1][2][3][4][5][6]. These materials require certain characteristics to be manageable in device applications [1,2,7].…”

Section: Introductionmentioning

confidence: 99%

Mesomorphic, Optical and DFT Aspects of Near to Room-Temperature Calamitic Liquid Crystal

et al. 2020

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A new liquid crystalline, optical material-based Schiff base core with a near to room-temperature mesophase, (4-methoxybenzylideneamino)phenyl oleate (I), was prepared from a natural fatty acid derivative, and its physical and chemical properties investigated by experimental and theoretical approaches. The molecular structure was confirmed by elemental analysis, FT-IR (Fourier-Transform-Infrared Spectroscopy) and NMR (nuclear magnetic resonance) spectroscopy. Optical and mesomorphic activities were characterized by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The results show that compound (I) exhibits an enantiotropic monomorphic phase comprising a smectic A phase within the near to room-temperature range. Ordinary and extraordinary refractive indices as well as birefringence with changeable temperatures were analyzed. Microscopic and macroscopic order parameters were also calculated. Theoretical density functional theory (DFT) calculations were carried out to estimate the geometrical molecular structures of the prepared compounds, and the DFT results were used to illustrate the mesomorphic results and optical characteristics in terms of their predicted data. Three geometrical isomers of the prepared compound were investigated to predict the most stable isomer. Many parameters were affected by the geometrical isomerism such as aspect ratio, planarity, and dipole moment. Thermal parameters of the theoretical calculations revealed that the highest co-planar aromatic core is the most stable conformer.

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Electro-optical properties of a new series of fluorinated antiferroelectric orthoconic liquid crystalline esters

Cited by 40 publications

References 46 publications

Static Permittivity and Electro-Optical Properties of Bi-Component Orthoconic Antiferroelectric Liquid Crystalline Mixtures Targeted for Polymer Stabilized Sensing Systems

Static Permittivity and Electro-Optical Properties of Bi-Component Orthoconic Antiferroelectric Liquid Crystalline Mixtures Targeted for Polymer Stabilized Sensing Systems

Preparation and Study of the Electro-optical Properties of Binary Mixtures of Orthoconic Anti-ferroelectric Esters and Achiral Phenyl Pyrimidine Liquid Crystal

Mesomorphic, Optical and DFT Aspects of Near to Room-Temperature Calamitic Liquid Crystal

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