β Dielectric relaxation mode in side-chain liquid crystalline polymer film

Okutan, Mustafa; Şentürk, E.

doi:10.1016/j.jnoncrysol.2007.08.085

Cited by 24 publications

(12 citation statements)

References 33 publications

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“…They probably have the same origin since their τ 0 parameters are, in fact, the same. In polymeric systems, β-relaxation has been attributed to noncooperative rotational or vibrational modes of motion in side groups ( [2,4,5,11] and references herein). In the DS work on SCLCPs, [2] two β-relaxations, β 1 and β 2 , have been revealed and attributed to rotations in the side group.…”

Section: Dielectric Behaviourmentioning

confidence: 99%

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Polyazomethine with m-tolylazo side groups: thermal, dielectric and conductive behaviour

et al. 2015

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2015): Polyazomethine with mtolylazo side groups: thermal, dielectric and conductive behaviour, Liquid Crystals, Using solution polycondensation, a new polyazomethine with m-tolylazo side groups (PAz) exhibiting thermotropic liquid crystalline phase was synthesised and its chemical structure was characterised with generally accepted methods. Its phase transition temperatures were detected with both polarising optical microscopy and differential scanning calorimetry. Using dielectric spectroscopy method, both real and imaginary parts of the permittivity were investigated in wide regions of temperature (from −100°C to 170°C) and frequency (from 1 Hz to 1 MHz). Analysis of frequency dependent permittivity allowed finding three relaxations (α, β 1 and β 2 ) in PAz. β-relaxations were described with the Arrhenius equation, whereas α-relaxation was described with the Vogel-Fulcher-Tammann equation. The alternating current conductivity (ACC) of PAz was studied in the same regions of temperature and frequency. The frequency dependent ACC was described with an exponent power equation. Presentation of ACC as a function of inverse temperature allowed us to describe ACC with the Arrhenius equation.

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Section: Dielectric Behaviourmentioning

confidence: 99%

“…Therefore, the dielectric spectroscopy (DS) method has been used extensively for investigation of LCs. [1][2][3][4][5][6][7][8][9][10] We should note the difference between dielectric response of low-molecular-weight LCs and polymer LCs. In low-molecular-weight LCs, rotation of whole molecules around their long/short axes can be seen.…”

Section: Introductionmentioning

confidence: 98%

Polyazomethine with m-tolylazo side groups: thermal, dielectric and conductive behaviour

et al. 2015

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“…Dielectric analysis of ion conducting polymer electrolytes can provide information on ion transport behavior and ionic/molecular interaction in solid polymer electrolytes [18]. This is due to the fact that dielectric constant is both frequency and temperature dependent [19]. Recently Petrowsky and Frech [20,21] hypothesized that the DC conductivity is not only a function of temperature, but also is dependent on the dielectric constant in organic liquid electrolytes.…”

Section: Introductionmentioning

confidence: 99%

Electrical Conduction Mechanism in Solid Polymer Electrolytes: New Concepts to Arrhenius Equation

Aziz

Abidin

2013

Journal of Soft Matter

110

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Solid polymer electrolytes based on chitosan NaCF 3 SO 3 have been prepared by the solution cast technique. X-ray diffraction shows that the crystalline phase of the pure chitosan membrane has been partially disrupted. The fourier transform infrared (FTIR) results reveal the complexation between the chitosan polymer and the sodium triflate (NaTf) salt. The dielectric constant and DC conductivity follow the same trend with NaTf salt concentration. The increase in dielectric constant at different temperatures indicates an increase in DC conductivity. The ion conduction mechanism follows the Arrhenius behavior. The dependence of DC conductivity on both temperature and dielectric constant ( dc ( , ) = 0 − / ) is also demonstrated.

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“…The complex dielectric function, ɛ∗, which consists of dielectric constant and loss in materials property depends on frequency, temperature, and structure. At low frequency both of them ( ε | and ε ǁ ) are very high due to EP effect . To reduce the effect of EP, Macedo and coworkers have established the electric modulus formalism .…”

Section: Resultsmentioning

confidence: 99%

Microstructural, wetting, and dielectric properties of plasma polymerized polypyrrole thin films

Koduru

Marino

Janardhanam

et al. 2016

J of Applied Polymer Sci

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Polypyrrole (PPy) thin films were synthesized by plasma polymerization technique and investigated the influence of discharge power on microstructural, optical, surface wettability, and dielectric properties of grown films. As deposited PPy films were characterized by X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR), Atomic force microscopy, UV-VIS spectroscopy and dielectric spectroscopy. The broad XRD peak present at 2u 5 23.58 revealed the amorphous nature of grown PPy films. The FTIR spectra displayed characteristic peaks in the wavenumbers regions 3300-3400 cm 21 and 1635-1700 cm 21 and respective peaks intensities decreased slightly as a function of discharge powers. Significant modifications in surface morphology of the films were observed as a function of discharge powers and PPy films synthesized at higher discharge power of 50 W demonstrated characteristic surface morphology composed of characteristic vertical cone shaped clusters provided with rms roughness of 3.42 nm. The UV-VIS absorption spectra evidenced that the optical density values varied as a function of discharge power. The evaluated band gap energies decreased with an increase of discharge power and found to be 2.53 eV for PPy films prepared at higher discharge power of 50 W. The surface wettability studies evidenced that as prepared PPy films were found to be hydrophilic in nature. The dielectric measurements were carried out for "ITO/polymer/ITO" structures in the frequency range 10 mHz to 100 kHz. As evidenced from dielectric spectroscopic measurements, PPy films synthesized at 50 W were demonstrated conductivity value of 6.0 3 10 212 S/m.

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β Dielectric relaxation mode in side-chain liquid crystalline polymer film

Cited by 24 publications

References 33 publications

Polyazomethine with m-tolylazo side groups: thermal, dielectric and conductive behaviour

Polyazomethine with m-tolylazo side groups: thermal, dielectric and conductive behaviour

Electrical Conduction Mechanism in Solid Polymer Electrolytes: New Concepts to Arrhenius Equation

Microstructural, wetting, and dielectric properties of plasma polymerized polypyrrole thin films

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