Surface Modified ${\rm CaTiO}_{3}$ Loaded in Polyaniline by Sodium Dodecyl Benzene Sulphonic Acid for Humidity Sensor

Parveen, Ameena; Koppalkar, Anilkumar; Roy, Aashis S.

doi:10.1109/jsen.2012.2203455

Cited by 25 publications

(8 citation statements)

References 23 publications

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“…19 The bands at 1560 cm À1 and 1486 cm Table 1 The relative thermal stability of the composites was compared by comparing the T 5 (temperature at which weight loss is 5%), T 10 (temperature for 10% weight loss), T 15 (temperature at which 15% weight loss was observed) and T max (temperature at the maximum weight loss) PANI 225 277 307 341 PBE111 231 303 321 335 PBE112 287 425 545 301 PBE121 255 303 327 329 stretching of aromatic amines. [23][24][25] These results are in good agreement with the previous spectroscopic characterization of PANI. 26,27 However, in the case of the nanocomposites, a slight shiing and broadening of the characteristic bands was observed which indicates the presence of physical interactions between PANI, BST and EG.…”

Section: Thermogravimetric Analysissupporting

confidence: 92%

Tailored polyaniline/barium strontium titanate/expanded graphite multiphase composite for efficient radar absorption

Sambyal¹,

Singh²,

Verma

et al. 2014

RSC Adv.

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The present paper reports the synthesis of a high-performance microwave absorbing material using a simple, cost-effective and scalable method by encapsulating barium strontium titanate (BST) and expanded graphite (EG) in a polyaniline (PANI) matrix. One of the formulations (higher content of BST) shows shielding effectiveness due to absorption of more than 50 dB (>99.9999% attenuation) with minimum reflection loss (#1 dB) in the Ku-band (12.4-18 GHz) frequency range. Another formulation (higher content of EG) shows a total shielding effectiveness of more than 81 dB with a reflection loss of 10 dB. In order to probe the relationship between the observed shielding response and the electromagnetic attributes, dielectric and permeability parameters have been calculated from the measured scattering parameters (S 11 , S 22 , S 12 , S 21 ) using the Nicolson-Ross-Weir algorithm. The synthesised formulations were characterized thoroughly using XRD, FTIR, TGA, UV, Raman spectroscopy, SEM and HRTEM. A. IntroductionElectromagnetic interference (EMI) among various devices such as cellular phones, televisions, weather radars, TV picture transmission, and telephone microwave relay systems 1 is the side-effect of the vast development in electronics and communication industries. Shielding at higher frequency, especially microwave radiation, continues to be a serious concern to ensure unperturbed performance of electronic items and to avoid any adverse effects on human health. To overcome this problem, lightweight EMI shielding materials are needed to protect the workspace and environment from radiation from computers and telecommunication equipment, as well as for protection for sensitive circuits. Conventionally, there are two ways of EMI shielding, either by complete reection or by total absorption of the radiation. Metals are generally employed for reection-based shielding, 2,3 but in the quest of absorptionbased shields, materials should possess optimum conductivity along with a high dielectric value.When electromagnetic radiation is incident on a shield, part of the incident wave is absorbed, some is reected from the surface and the rest is transmitted through the shield. Hence, the total EMI shielding effectiveness (SE T ) is the sum of the contributions from absorption (SE A ), reection (SE R ) and transmission or multiple reections (SE M ). However, when SE T > 10 dB, SE M can be ignored.4,5 Furthermore, the effective absorbance (A eff ) can be described as A eff ¼ (1 À R À T)/(1 À R) with respect to the power of the effectively incident EM wave inside the shielding material, where R and T are the reectance and transmittance coefficients. For a material, the skin depth (d) is the distance up to which the intensity of the EM wave decreases to 1/e of its original strength. d is related to the angular frequency, relative permeability and total conductivity, s T ¼ (s dc + s ac ). According to EM theory, for electrically thick samples (t > d), the frequency (u) dependence of far eld losses can be expressed in terms of...

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Section: Thermogravimetric Analysissupporting

confidence: 92%

Tailored polyaniline/barium strontium titanate/expanded graphite multiphase composite for efficient radar absorption

Sambyal¹,

Singh²,

Verma

et al. 2014

RSC Adv.

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“…At higher temperatures, the conductivity increases because of the hopping of polarons from one localized site to another. The temperature dependence of conductivity of the composites exhibits a typical semiconductor behavior, and it can be expressed by the one‐dimensional variable range hopping model proposed by Mott as follows,

σ ((), T) = σ_{0} exp ([], ‐ {({normalT}_{0} / T)}^{1 true/ 2})

T_{0} = 8 normalα true/ normalZ normalN ((), normalE normalF) normalK normalB

…”

Section: Electrical Property Measurementsmentioning

confidence: 99%

Synthesis, characterization, dielectric and rectification properties of PANI/Nd₂O₃:Al₂O₃nanocomposites

Ansari¹,

Khasim

Parveen³

et al. 2016

Polym. Adv. Technol.

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nanocomposites were prepared by in situ oxidative polymerization method using different weight percentages of oxide powders. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy and X-ray diffraction for molecular and crystal structures. Scanning electron microscopy and transmission electron microscopy images show the tubular structure of polyaniline nanocomposite with embedded metal oxides. The electrical conductivity of the nanocomposites increases with increase in temperature as well as with concentration of Nd 2 O 3 :Al 2 O 3 particles in polyaniline. This is because of the hopping of charge polarons and extended chain length of the nanocomposites as evidenced by the negative thermal coefficient (NTC) characteristic. A high NTC value of 2.67 was found in nanocomposites with 15 wt% of oxide particles. These nanocomposites show low dielectric constant and dielectric loss; the electrical conductivity is higher than 0.3 S/cm as confirmed by Cole-Cole plot that indicates a decrease in both grain resistance and bulk resistance of the nanocomposites. The current-voltage and capacitance-voltage measurements were also carried out. The carrier mobility μ values of pure polyaniline and nanocomposites were found to be 4.27 × 10 À3 and 1.45 × 10 -2 H.M À1 , respectively. A significant enhancement in carrier mobility was observed in comparison with the literature.

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“…High values of permittivity at lower frequency range are due to maximum accumulated charge carriers at the interface of grain boundaries. The strong frequency dispersion of permittivity is observed in the low frequency region [19]. The observed behavior may be due to dipole polarization along with Maxwell-Wagner-Sillars (MWS) polarization [20] at the interface of electrode and nanocomposites surface taking place in these materials lead to a large dispersion throughout the frequency range.…”

Section: Dielectric Studiesmentioning

confidence: 96%

Conductivity of surface modified TiO 2 dope nanocomposites

Nagaraju

Roy²,

Ramgopal³

2015

Measurement

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Surface Modified ${\rm CaTiO}_{3}$ Loaded in Polyaniline by Sodium Dodecyl Benzene Sulphonic Acid for Humidity Sensor

Cited by 25 publications

References 23 publications

Tailored polyaniline/barium strontium titanate/expanded graphite multiphase composite for efficient radar absorption

Tailored polyaniline/barium strontium titanate/expanded graphite multiphase composite for efficient radar absorption

Synthesis, characterization, dielectric and rectification properties of PANI/Nd₂O₃:Al₂O₃nanocomposites

Conductivity of surface modified TiO 2 dope nanocomposites

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Surface Modified ${\rm CaTiO}_{3}$ Loaded in Polyaniline by Sodium Dodecyl Benzene Sulphonic Acid for Humidity Sensor

Cited by 25 publications

References 23 publications

Tailored polyaniline/barium strontium titanate/expanded graphite multiphase composite for efficient radar absorption

Tailored polyaniline/barium strontium titanate/expanded graphite multiphase composite for efficient radar absorption

Synthesis, characterization, dielectric and rectification properties of PANI/Nd2O3:Al2O3nanocomposites

Conductivity of surface modified TiO 2 dope nanocomposites

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Synthesis, characterization, dielectric and rectification properties of PANI/Nd₂O₃:Al₂O₃nanocomposites