Frequency Tuned Dielectric and Electrical Properties of a Thermotropic Liquid Crystal Compound 9OBA.

Patari, Sangita; Nath, A.

doi:10.1016/j.matpr.2017.09.207

Cited by 2 publications

(4 citation statements)

References 16 publications

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“…Equation (8) can also be written in the following form, considering:

σ DC

where σ DC represents the DC conductivity, f c stands for the characteristic frequency, and n is a parameter, which represents the degree of interaction between the mobile ions and their surroundings. The value of n is normally situated between 0 and 1, however some authors have found values where n > 1 [ 33 , 34 , 35 , 36 ]. Many other models are available to analyze the frequency dependence of the complex conductivity like Cole–Cole, Cole–Davidson, Havriliak–Negami, or Kohlrausch–Williams–Watts functions transformed beforehand into their conductivity representations [ 37 , 38 , 39 , 40 , 41 ].…”

Section: Resultsmentioning

confidence: 99%

“…When n becomes smaller than 1, the process of charge carrier displacement involves a translational motion with a sudden jump. When n > 1, the movement involves a localized jump of the charge carriers that will leave their neighborhood completely [ 36 ]. Some research groups reported about n values with n > 1.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 4 illustrates the real component (σ') of the complex conductivity (σ*) in homogeneous and homeotropic alignments on a frequency range from 0.1 Hz to 1 MHz, obtained from Equation (6). The dielectric conductivity represents a process that combines jumps, mobility, and transport of charge carriers present in the material [4,36]. At lower frequencies (<1 Hz), σ' starts to decrease.…”

Section: Frequency Dependence Of Real Conductivity For Non-purified Purified and Nanoparticle Doped Lc Mixturesmentioning

confidence: 99%

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Dielectric Spectroscopy Analysis of Liquid Crystals Recovered from End-of-Life Liquid Crystal Displays

et al. 2021

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In the present work, the dielectric properties of recycled liquid crystals (LCs) (non-purified, purified, and doped with diamond nanoparticles at 0.05, 0.1, and 0.2 wt%) were investigated. The studied LC mixtures were obtained from industrial recycling of end-of-life LC displays presenting mainly nematic phases. Dielectric measurements were carried out at room temperature on a frequency range from 0.1 to 106 Hz using an impedance analyzer. The amplitude of the oscillating voltage was fixed at 1 V using cells with homogeneous and homeotropic alignments. Results show that the dielectric anisotropy of all purified samples presents positive values and decreases after the addition of diamond nanoparticles to the LC mixtures. DC conductivity values were obtained by applying the universal law of dielectric response proposed by Jonscher. In addition, conductivity of the doped LC mixtures is lower than that of the undoped and non-purified LC.

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“…Equation (8) can also be written in the following form, considering:

σ DC

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Frequency Dependence Of Real Conductivity For Non-purified Purified and Nanoparticle Doped Lc Mixturesmentioning

confidence: 99%

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Dielectric Spectroscopy Analysis of Liquid Crystals Recovered from End-of-Life Liquid Crystal Displays

et al. 2021

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“…To date, there has been much research on thermotropic liquid crystalline compounds. This research focused on the optical measurements, ion-responsive properties, photoconductivity, and dielectric studies [ 22 , 23 , 24 , 25 ]. However, there are no studies on cinnamaldehyde-based compounds bearing different terminal groups at the periphery.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Determination of Thermotropic Liquid Crystalline Behavior of Cinnamaldehyde-Based Molecules with Two Schiff Base Linking Units

2020

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A series of liquid crystal molecules with two Schiff base linking units and a cinnamaldehyde core with different terminal groups were synthesized and characterized. The intermediates of 4-heptyloxybenzaldehyde (1a) and 4-dodeyloxybenzaldehyde (1b) were synthesized through the alkylation of 4-hydroxybenzaldehyde with a series of bromoalkane. A condensation reaction of cinnamaldehyde, 1,4-phenylenediamine and a series of substituted benzaldehydes with different terminal groups such as bromo, chloro, hydroxy, cinnamaldehyde, hydrogen, methoxy, heptyloxy and dodecyloxy produced a series of new cinnamaldehyde-based compounds, 2–9, respectively. All these compounds were characterized using Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and CHN elemental analysis. The liquid crystal properties of these compounds were determined using polarized optical microscopy (POM), and their transitions were further confirmed using differential scanning calorimetry (DSC). Compounds with chloro, bromo, methoxy, heptyloxy, and dodecyloxy substituents are mesogenic compounds with nematic phase behavior. However, the other compounds were found to be non-mesogenic without any mesophase transitions. The structure–property relationship was investigated in order to study the effect of different terminal groups and Schiff base linking units on the liquid crystalline behavior of these compounds.

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Frequency Tuned Dielectric and Electrical Properties of a Thermotropic Liquid Crystal Compound 9OBA.

Cited by 2 publications

References 16 publications

Dielectric Spectroscopy Analysis of Liquid Crystals Recovered from End-of-Life Liquid Crystal Displays

Dielectric Spectroscopy Analysis of Liquid Crystals Recovered from End-of-Life Liquid Crystal Displays

Synthesis and Determination of Thermotropic Liquid Crystalline Behavior of Cinnamaldehyde-Based Molecules with Two Schiff Base Linking Units

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