Dielectric Properties, AC Conductivity, and Electric Modulus Analysis of Bulk Ethylcarbazole‐Terphenyl

Abstract

Electrical and dielectric properties for bulk ethylcarbazole-terphenyl (PEcbz-Ter) have been studied over frequency range 1 kHz–2 MHz and temperature range (R.T –120°C). The copolymer PEcbz-Ter was characterised by using X-ray diffraction. The frequency dependence of the dielectric constant (εr′) and dielectric loss (εr″) has been investigated using the complex permittivity. εr′ of the copolymer decreases with increasing frequency and increases with temperature. AC conductivity (σac) data were analysed by the universal power law. The behaviour of σac increases with increasing temperature and frequency. The change of the frequency exponent (s) with temperature was analysed in terms of different conduction mechanisms, and it was found that the correlated barrier-hopping model is the predominant conduction mechanism. The electric modulus was used to analyze the relaxation phenomenon in the material.

Novel solid biopolymer electrolyte based on methyl cellulose with enhanced ion transport properties

“…The complex permittivity ε r * (ω) of the polymer electrolyte is a combination of dielectric properties of the system, as shown below 45 where ε′ (ω) is dielectric constant, and ε″ (ω) represents the dielectric loss of the system, which can be expressed as 72 : where C p is the capacitance of the sample, d is the thickness of the sample, A is the electrode area, tanδ is the loss factor, and ε 0 is the permittivity of free space (8.85 × 10 −12 F/m). C p and tanδ were obtained directly from the measurements.…”

“…AC conductivity of the electrolytes was calculated using the following expression: 72 where ε 0 represents the permittivity of free space (8.85 × 10 −12 F/m), ε″ is the dielectric loss of the electrolytes and ω is the angular frequency. Figure 12 shows the variation of log σ with log f of pristine polymer and polymer electrolyte samples with different concentrations of magnesium nitrate salt.…”

Humidity Sustainable Hydrophobic Poly(vinylidene fluoride)-Carbon Nanotubes Foam Based Piezoelectric Nanogenerator

“…The dielectric constant (ε′) of the foam was calculated and found to be 3048 at low frequency range of 150 Hz, which attains a low value of 120 at a frequency of 2 MHz. At the lower frequency side, electric dipoles can respond and follow under the applied electric field, while with the increase of frequency, electric dipoles are unable to respond and follow with the applied ac frequency, which results dielectric constant decreases. , Further, an exponential decrease in dielectric constant with increase of frequency can be ascribed to a contributions of electronic, ionic, and space charge/interfacial polarization. − The enhancement of dielectric constant may be considered as a natural result of the emergence of spontaneous polarization in PVDF foam due to local electric field induced by the CNT. − Furthermore, such large value of dielectric constant as compared to pure PVDF film is due to the rapid increase in the dipole moment per unit volume cause by nanoscale size of PVDF-CNT which act as nano dipoles under the application of electric field. − Variation of dielectric loss (tan δ) with frequency (20 Hz-2 MHz) is shown in Figure b. Dielectric loss tangent also exhibits a similar trend and tan δ of 34.55 was observed at 150 Hz.…”

Experimental Investigation of E-beam Effect on Electric Field Distribution in Cross-Linked Polyethylene/ZnO Nanocomposites for Medium-Voltage Cables Simulated Using COMSOL Multiphysics

“…As a result, ε′ decreases until it approaches a constant value at a higher frequency, which corresponds to interfacial polarization. It has a greater dielectric constant than many other aromatic organic polymers, making it a suitable semiconductor material [42]. In contrast, with the irradiated XLPE/ZnO nanocomposite, the real part of permittivity rose substantially.…”