Synthesis, Electrical Conductivity, and Dielectric Behavior of Polyaniline/V2O5Composites

Conducting polymer composites of polyaniline/vanadium pentaoxide PANI/V2O5(with different initial weight percentage of V2O5) has been synthesized byin situpolymerization method. DC conductivity of compressed pellets has been analyzed in the temperature range 300–550 K and was found to increase with V2O5doping. This increase in conductivity is mainly due to band conduction. It has also been observed that the dielectric constant and dielectric loss increase with the level of doping of V2O5but remain independent of the frequency (50 KHz–1 MHz). X-ray diffraction pattern shows some order of crystallinity of composites due to interaction of polyaniline with V2O5. UV-visible spectroscopy shows an increase in the optical band gap with doping.

Synthesis, Growth, and Electrical Transport Properties of Pure and -Doped Triglycine Sulphate Crystal

Pure triglycine sulphate (TGS) and LiSO4-doped TGS crystals were grown from aqueous solution by natural evaporation method. The grown crystals were characterized by UV-vis spectroscopy, electrical conductivity () measurement, dielectric studies, microhardness, and thermogravimetry/differential thermal analysis. Pure TGS and LiSO4-doped TGS crystals were found highly transparent and full faced. The direct current conductivity is found to increase with temperature as well as dopant concentrations. Curie temperature remains the same for pure and doped crystals, but dielectric constant and dielectric loss increase with dopant concentration. The Vicker’s microhardness of the LiSO4-doped TGS crystals along (001) face is found higher than that of pure TGS crystals. Etching studies illustrate the quality of the doped crystal. The experimental results evidence the suitability of the grown crystal for optoelectronic applications.

Dielectric Property of Laminated AlN/BN Ceramic Composites

The relationship between the processing technology and the dielectric property of the laminated AlN/h-BN ceramic composites has been studied. The results showed that the main polarization mechanism of laminated ceramic composites in low frequency range is space charge polarization at the interface of AlN layer and BN layer. Due to the affection of porosity, the permittivity increases and the dielectric loss decreases with increasing the hot pressing temperature. The permittivity increases and the dielectric loss decreases with increasing thickness ratio of different layer., Both permittivity and dielectric loss increase with increasing the content of AlN doping in BN layer.

Effect of CaTiO3 Content on the Dielectric Properties of Ba0.5Sr0.5TiO3

In this paper, a microwave material (Ba0.85Ca0.15)0.5Sr0.5TiO3 with 5 wt% MgO additive was prepared by traditional solid-state reactions, i.e., mixing BaTiO3 and SrTiO3 powders and then doping CaTiO3 and MgO. It was found that, with the increasing CaTiO3 content, the dielectric constant of the resultant material decreases and the tunability and dielectric loss increase.

Ambient Electrical Properties of Mica-Styrene-Butadiene Rubber Composites

We have studied the effect of addition of (a) mica, (b) silane coupling agent, and (c) silane-treated mica on the ambient dielectric properties of vulcanized styrene-butadiene rubber. It is observed that both dielectric constant and dielectric loss increase as mica, silane, and silane-treated mica are added. The increase is more pronounced in the case of silane-treated mica than for the untreated mica systems. The observed values of dielectric constants are in close agreement with the calculated ones obtained from different theories of heterogeneous dielectrics. Dielectric strength shows an increasing trend in the presence of mica. At higher mica loading, D.C. conductivity decreases slightly.