Dielectric behavior and AC electrical conductivity analysis of PMMA films

PMMA films of different thickness (0.006, 0.0105, 0.0206, 0.0385 and 0.056cm) were synthesized by casting process. The temperature and frequency dependence of dielectric constant and AC electrical conductivity measurements at various frequencies (10kHz-10MHz) and temperatures (293-373K) were carried out. Few anomalies in dielectric studies were observed near 313 and 373 K respectively. These points were related to glass transitions temperature. The variation of activation energy and conduction behavior was studied .From the AC conduction studies, it is confirmed that the mechanism responsible for the conduction process is hopping of carriers. The variations of the dielectric constant and loss as function of frequency at different temperature was observed and the results were discussed. The calculated activation energy varied with the thickness, temperature, and applied frequency. Conductivity plots against frequency suggested that the response obeying the universal power law concerning the AC conductivity and dielectric behavior of polymer. The polarizability a increases with temperature but decreases with thickness indicating weekends and rising of intermolecular forces respectively.

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Analysis of X-ray structure, dielectric properties and AC conductivity of (4E)-2-amino-3-cyanobenzo[b]oxocin-6-one

Materials Science-Poland ◽

10.1515/msp-2016-0044 ◽

2016 ◽

Vol 34 (2) ◽

pp. 386-392 ◽

Cited By ~ 4

Author(s):

H.A.M. Ali ◽

Magdy A. Ibrahim

Keyword(s):

Crystal Structure ◽

Activation Energy ◽

Electrical Conductivity ◽

Dielectric Constant ◽

Relaxation Time ◽

Conductivity Measurements ◽

X Ray Diffraction ◽

Ac Electrical Conductivity ◽

X Ray ◽

Different Temperatures

AbstractThe crystal structure of (4E)-2-amino-3-cyanobenzo[b]oxocin-6-one, denoted as 4(E)-ACBO, was analyzed using X-ray diffraction technique. The dielectric and AC electrical conductivity measurements of the bulk 4(E)-ACBO in the form of pellet were studied in the range of frequency 42 Hz to 5 MHz and the temperature range of 303 K to 373 K. The temperature and frequency dependence of dielectric constant (∊1), dielectric loss (∊2) and AC electrical conductivity (σAC) were investigated. The relaxation time (τ) for electrons to hop over a barrier of height WH was calculated at different temperatures. The AC activation energy was determined from the temperature dependence of σAC at different frequencies.

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Dependence of Electrical Properties on Frequency and Temperature for Novel Cyclopentenone Derivatives

Nanoarchitectonics ◽

10.37256/nat.11202077.13-25 ◽

2020 ◽

Vol 1 (1) ◽

pp. 13-25

Author(s):

Salama A. H.

Keyword(s):

Activation Energy ◽

Electrical Conductivity ◽

Dielectric Constant ◽

Electrical Properties ◽

Arrhenius Equation ◽

Charge Carriers ◽

Frequency Range ◽

Ac Electrical Conductivity ◽

Dc Electrical Conductivity ◽

Arrhenius Relation

Electrical properties of some new cyclopentenone derivatives have been studied. The structures of prepared samples were characterized by (UV), (XRD) and (SEM). The dependence of electrical properties such as σdc , σac , ɛ' and ɛ'' on frequency and temperature were studied at frequency range from 50 Hz to 5 MHz and the temperature range from 25oC to 140oC. It was found that, ɛ' decreased with increasing frequency while it increases with increasing temperatures within the used ranges. Moreover, dielectric constant is structural dependent which is obvious from the variation of dielectric constant for each sample. Ac-electrical conductivity increased with increasing frequency which was attributed to the polarization of the charge carriers. The temperature dependence of dc-electrical conductivity show typical Arrhenius relation for the three prepared samples. The activation energy calculated from Arrhenius equation and the results are discussed in detailed.

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PS/PANI/MoS2 Hybrid Polymer Composites with High Dielectric Behavior and Electrical Conductivity for EMI Shielding Effectiveness

Materials ◽

10.3390/ma12172690 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2690 ◽

Cited By ~ 6

Author(s):

Saboor ◽

Khalid ◽

Jan ◽

Khan ◽

Farooq ◽

...

Keyword(s):

Electrical Conductivity ◽

Dielectric Constant ◽

Polymer Composites ◽

Dielectric Behavior ◽

Hybrid Polymer ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Emi Shielding Effectiveness ◽

Dielectric Constant And Loss ◽

High Dielectric

Liquid exfoliated molybdenum disulfide (MoS2) nanosheets and polyaniline (PANI) nanoparticles are dispersed in polystyrene (PS) matrix to fabricate hybrid polymer composites with high dielectric and electromagnetic interference (EMI) shielding behavior. A phase-separated morphology is formed when PANI and MoS2 are incorporated into polystyrene (PS) matrix. An increasing concentration of MoS2 nanoparticles inside PS/PANI (5 wt %) polymer blend forms an interconnected network, resulting in high electrical conductivity and dielectric behavior, making them a suitable candidate for EMI shielding application. An increment in dielectric constant and loss, up to four and five orders of magnitude, respectively, is recorded at a maximum concentration of 1 wt % of MoS2 in PS/PANI-5 polymer blend at 100 Hz. The enhanced dielectric characteristics for PS/PANI/MoS2 composites are then theoretically evaluated for the estimation of EMI shielding effectiveness in the frequency range of 100 Hz to 5 MHz. The maximum dielectric constant and loss achieved for PS/PANI-5 wt %/MoS2-1 wt % are responsible for estimated shielding effectiveness of around 92 dB at 100 Hz. The increase in dielectric behavior and shielding effectiveness is probably due to the increased number of charged dipoles accumulated at the insulator–conductor interface.

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Structural and Dielectric Properties of (1-x) (Al0.2La0.8TiO3) + (x) (BiZnFeO3) (x = 0.2 - 0.8) Nanocomposites

10.21203/rs.3.rs-493976/v1 ◽

2021 ◽

Author(s):

A. Mallikarjuna ◽

N. Suresh Kumar ◽

T. Anil Babu ◽

S. Ramesh ◽

Chandra Babu Naidu K

Keyword(s):

Electrical Conductivity ◽

Dielectric Constant ◽

Phase Transformation ◽

Dielectric Properties ◽

Dielectric Behavior ◽

Perfect Absorber ◽

X Ray Diffraction ◽

Ac Electrical Conductivity ◽

X Ray ◽

Diffraction Patterns

Abstract (1-x) (Al0.2La0.8TiO3) + (x) (BiZnFeO3) (x = 0.2 - 0.8) [ALTBZFO] nanocomposites were synthesized via hydrothermal method. The X-ray diffraction patterns indicated the phase transformation from tetragonal to cubic for x = 0.2 to 0.4 - 0.8 samples, respectively. The surface morphology showed the existence of nanospheres like structures. At 1 MHz frequency also, the dielectric constant was increased from 230 to 710 for x = 0.2 – 0.6 samples, respectively. But, interestingly, x = 0.6 nanocomposite exhibited the negative dielectric behavior having the dielectric constant (ε') ~ -58.5 and dielectric loss (ε") ~ -417 at 8 MHz. Likewise, x = 0.6 sample showed ac-electrical conductivity (σac) -0.159 S/cm at 6 MHz. Hence, these kinds of materials can provide high charge stored capacitor, and perfect absorber applications.

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ON THE DIELECTRIC BEHAVIOR OF LiCo3/5Fe2/5VO4 CERAMICS

Modern Physics Letters B ◽

10.1142/s0217984910022731 ◽

2010 ◽

Vol 24 (07) ◽

pp. 665-670

Author(s):

MOTI RAM

Keyword(s):

Activation Energy ◽

Dielectric Constant ◽

Frequency Dependence ◽

Chemical Method ◽

Arrhenius Plot ◽

Dielectric Behavior ◽

Tangent Loss ◽

Low Frequencies ◽

Different Temperatures ◽

Tan Δ

The LiCo 3/5 Fe 2/5 VO 4 ceramics has been fabricated by solution-based chemical method. Frequency dependence of the dielectric constant (εr) at different temperatures exhibits a dispersive behavior at low frequencies. Temperature dependence of εr at different frequencies indicates the dielectric anomalies in εr at Tc (transition temperature) = 190°C, 223°C, 263°C and 283°C with (εr) max ~ 5370, 1976, 690 and 429 for 1, 10, 50 and 100 kHz, respectively. Frequency dependence of tangent loss ( tan δ) at different temperatures indicates the presence of dielectric relaxation in the material. The value of activation energy estimated from the Arrhenius plot of log (τd) with 103/T is ~(0.396 ± 0.012) eV.

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