Interpretation of X-ray Powder Diffraction Patterns . By H. Lipson and H. Steeple. Pp. viii + 335 + 3 plates. (Mac-millan: London; St Martins Press: New York, May 1970.) £4.

X-Ray Diffraction

Progress in preparation, processing and applications of polyaniline

Dielectric polymer nanocomposites are rapidly emerging as novel materials for a number of advanced engineering applications. In this Review, we present a comprehensive review of the use of ferroelectric polymers, especially PVDF and PVDF-based copolymers/blends as potential components in dielectric nanocomposite materials for high energy density capacitor applications. Various parameters like dielectric constant, dielectric loss, breakdown strength, energy density, and flexibility of the polymer nanocomposites have been thoroughly investigated. Fillers with different shapes have been found to cause significant variation in the physical and electrical properties. Generally, one-dimensional and two-dimensional nanofillers with large aspect ratios provide enhanced flexibility versus zero-dimensional fillers. Surface modification of nanomaterials as well as polymers adds flavor to the dielectric properties of the resulting nanocomposites. Nowadays, three-phase nanocomposites with either combination of fillers...

Recent Progress on Ferroelectric Polymer-Based Nanocomposites for High Energy Density Capacitors: Synthesis, Dielectric Properties, and Future Aspects.

The roles of green chemistry in nanotechnology and nanoscience fields are very significant in the synthesis of diverse nanomaterials. Herein, we report a green chemistry method for synthesized colloidal silver nanoparticles (Ag NPs) in polymeric media. The colloidal Ag NPs were synthesized in an aqueous solution using silver nitrate, polyethylene glycol (PEG), and β-D-glucose as a silver precursor, stabilizer, and reducing agent, respectively. The properties of synthesized colloidal Ag NPs were studied at different reaction times. The ultraviolet-visible spectra were in excellent agreement with the obtained nanostructure studies performed by transmission electron microscopy (TEM) and their size distributions. The Ag NPs were characterized by utilizing X-ray diffraction (XRD), zeta potential measurements and Fourier transform infrared (FT-IR). The use of green chemistry reagents, such as glucose, provides green and economic features to this work.

https://www.mdpi.com/1422-0067/13/6/6639/pdf

Synthesis and characterization of polyethylene glycol mediated silver nanoparticles by the green method

A unique nanostructured polyaniline (PANI)/mesoporous TiO(2) composite was synthesized and explored as an anode in Escherichia coli microbial fuel cells (MFCs). The results of X-ray diffraction, morphology, and nitrogen adsorption-desorption studies demonstrate a networked nanostructure with uniform nanopore distribution and high specific surface area of the composite. The composite MFC anode was fabricated and its catalytic behavior investigated. Optimization of the anode shows that the composite with 30 wt % PANI gives the best bio- and electrocatalytic performance. A possible mechanism to explain the excellent performance is proposed. In comparison to previously reported work with E. coli MFCs, the composite anode delivers 2-fold higher power density (1495 mW/m(2)). Thus, it has great potential to be used as the anode for a high-power MFC and may also provide a new universal approach for improving different types of MFCs.

Nanostructured polyaniline/titanium dioxide composite anode for microbial fuel cells

Dielectric and magneto-dielectric properties of nickel-coated multiwalled carbon nanotube filler-reinforced poly(vinylidene fluoride) flexible films

The current biomedical appliances require nano biomaterials with promising dielectric and transport properties. For this purpose, expensive, complicated instrumentations or time-consuming synthesis procedures, reducing acceptability of the developed materials, must be excluded. Therefore, for an effective solution to these challenges, proper scaling of electrical properties of nontoxic bioceramics is necessary by choosing eco-friendly surfactant-assisted synthesis methods. The present paper reports Polyvinylpyrrolidone-assisted hydrothermal synthesis of cupric oxide-hydroxyapatite nanocomposite (CuO-HAp-PVP) with crystallite size 25 nm. As observed by electron microscopy, the uniaxial growth of the CuO-HAp-PVP nanostructures elucidate novel flower-like aggregation. The nano-metric attachments of CuO phases are observed on the mesoporous surface (specific area of ∼17.7 m2/g obtained from Brunauer–Emmett–Teller study). The polymeric surfactant-mediated amorphous phases generate internal heterojunctions influencing the polarization process. The dielectric behavior [permittivity ∼6 × 103] and ionic conductivity of the nanocomposite are hence improved. Trap state-dependent bulk carrier conduction is observed by the nonlinear current-voltage characteristics. 

Effect of surfactant-assisted hierarchical growth of cupric oxide-hydroxyapatite nanocomposite on the dielectric and electrical transport behavior

In the present investigation, we have synthesized terbium (Tb) doped nickel ferrite (NFO) nanoparticles in sol- gel technique. The presence of the orthorhombic phase of terbium ferrite (TbFeO3) is observed, other than nickel ferrite (NFO) phase. Observed DC and AC conductivities are explained by Arrhenius equation and CBH model respectively. Activation energy is enhanced in higher temperature region than lower temperature. The creation of permanent polarization gives a loop in I-V spectroscopy study at 313 K. This hysteresis behaviour may have potential application in storage devices. The high value of dielectric constant (360 at T=303 K) is achieved by Tb+3 doping in NFO nanoparticles. Electric modulus study confirms the presence of a non-Debye type of relaxation behaviour within the Tb-NFO nanoparticles.

Investigation of enhanced dielectric and electrical properties of terbium doped nickel ferrite nanoparticles

A systematic investigation on electron dephasing scattering rate ( τ φ − 1 ) in Pd100-xAgx at low temperature has been reported. The dephasing scattering rate is dominating by electron-phonon scattering and follows the saturation behaviour for the temperature T → 0 K . The nature of zero temperature dephasing scattering rates cannot be explained by the existing mechanisms and it depends strongly on disorder. Both the electron-phonon coupling coefficient ( A e − p h ) and the zero temperature dephasing scattering rates ( τ 0 − 1 ) follow linear behaviour on mean free path ( l e ) . The magnitude of zero temperature dephasing time ( τ 0 ) increases with increasing disorder, may be due to incomplete momentum randomization by small angle scattering which suggests the requirement of long lime to loss the momentum correlation between initial and final state.

Disorder dependence zero temperature dephasing scattering rate in disordered Pd100-xAgx alloys

Electrical resistivity and magnetoresistivity of Ti3Ir compound have been measured in the temperature range 2.0 K ≤T ≤ 300 K in absence as well as in presence of magnetic field upto 7.7 T. The low temperature resistivity shows aT2 behaviour whereas the high temperature resistivity shows a linear behaviour. The magnetoresistivity is positive and cannot be explained by simple s-d scattering model. The enhancement of the coefficient A of theT2 term and the deviation from the quadratic field dependence of the resistivity may be due to the anisotropy in the compound.

Ajit Kumar Meikap

Papers

Dielectric and magneto-dielectric properties of nickel-coated multiwalled carbon nanotube filler-reinforced poly(vinylidene fluoride) flexible films

Effect of surfactant-assisted hierarchical growth of cupric oxide-hydroxyapatite nanocomposite on the dielectric and electrical transport behavior

Investigation of enhanced dielectric and electrical properties of terbium doped nickel ferrite nanoparticles

Disorder dependence zero temperature dephasing scattering rate in disordered Pd100-xAgx alloys

Transport properties of Ti3Ir compound at low temperature