Conducting polyaniline/ZnFe_(2)O_(4) nanocomposites are synthesized by using a simple and inexpensive one-step in-situ polymerization method in the presence of ZnFe2O4 nanoparticles.The structural,morphological and el...Conducting polyaniline/ZnFe_(2)O_(4) nanocomposites are synthesized by using a simple and inexpensive one-step in-situ polymerization method in the presence of ZnFe2O4 nanoparticles.The structural,morphological and electrical properties of the samples are characterized by x-ray diffraction,Fourier transform infrared spectra and scanning electron microscopy.These results reveal the formation of polyaniline/ZnFe2O4 nanocomposites.The morphology of these samples is studied by scanning electron microscopy.Further,the ac conductivity(σac)of these composites is investigated in the frequency range of 1 kHz–10 MHz.The presence of polarons and bipolarons are responsible for the frequency dependence of ac conductivity in these nanocomposites.The ac conductivity is found to be constant up to 1MHz and thereafter it increases steeply.The ac conductivity of 0.695 S・cm^(−1) at room temperature is observed as the maxima for the polyaniline with 40wt%of the ZnFe2O4 nanocomposite.展开更多
The polyaniline(PANI)/CoFe_(2)O_(4)nanocomposites were prepared by an in situ polymerization of aniline in an aqueous solution.The composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FTI...The polyaniline(PANI)/CoFe_(2)O_(4)nanocomposites were prepared by an in situ polymerization of aniline in an aqueous solution.The composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectrum,thermogravimetric analysis(TGA)and scanning electron micrograph(SEM).The AC conductivity and dielectric properties of these composites were investigated in the frequency range 1 kHz10 MHz at room temperature.The AC conductivity was found to be constant up to 1 MHz and thereafter it increases steeply and it was observed maximum for the PANI with 60 wt%of CoFe_(2)O_(4)nanocomposite.At lower frequencies the values of dielectric constant is maximum for pure CoFe_(2)O_(4)nanoparticles.展开更多
ZnO nanoparticles of different sizes were prepared by varying the molar ratio of glycine and zinc nitrate hexahydrate as fuel and oxidizer （0.1, 0.8, 1.11, 1.3, 1.5, 1.7, 2.0） by simple solution combustion method. U...ZnO nanoparticles of different sizes were prepared by varying the molar ratio of glycine and zinc nitrate hexahydrate as fuel and oxidizer （0.1, 0.8, 1.11, 1.3, 1.5, 1.7, 2.0） by simple solution combustion method. UV-Visible spectrophotometry studies show that, the band gap of the prepared ZnO nanoparticles increases with increasing fuel to oxidant （F/O） molar ratio up to 1.7 revealing the formation of ZnO nanoparticles. The decrease in band gap for the sample of F/O molar ratio 2.0 is due to an increase in particle size. Powder X-ray diffraction patterns of the prepared samples show the formation of single phase ZnO nanoparticles and the particle size decreases with increasing F/O molar ratio up to 1.7. Surface morphology of the prepared samples was studied by scanning electron microscopy and it was observed that, the porosity increases with increasing F/O molar ratio. DC electrical conductivity at room temperature and in the temperature range of 303-563 K was studied for all the samples and the results revealed that, the sample of F/O molar ratio 1.7 has low electrical conductivity at room temperature and high EAR （high temperature activation energy） compared to other samples.展开更多
文摘Conducting polyaniline/ZnFe_(2)O_(4) nanocomposites are synthesized by using a simple and inexpensive one-step in-situ polymerization method in the presence of ZnFe2O4 nanoparticles.The structural,morphological and electrical properties of the samples are characterized by x-ray diffraction,Fourier transform infrared spectra and scanning electron microscopy.These results reveal the formation of polyaniline/ZnFe2O4 nanocomposites.The morphology of these samples is studied by scanning electron microscopy.Further,the ac conductivity(σac)of these composites is investigated in the frequency range of 1 kHz–10 MHz.The presence of polarons and bipolarons are responsible for the frequency dependence of ac conductivity in these nanocomposites.The ac conductivity is found to be constant up to 1MHz and thereafter it increases steeply.The ac conductivity of 0.695 S・cm^(−1) at room temperature is observed as the maxima for the polyaniline with 40wt%of the ZnFe2O4 nanocomposite.
文摘The polyaniline(PANI)/CoFe_(2)O_(4)nanocomposites were prepared by an in situ polymerization of aniline in an aqueous solution.The composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectrum,thermogravimetric analysis(TGA)and scanning electron micrograph(SEM).The AC conductivity and dielectric properties of these composites were investigated in the frequency range 1 kHz10 MHz at room temperature.The AC conductivity was found to be constant up to 1 MHz and thereafter it increases steeply and it was observed maximum for the PANI with 60 wt%of CoFe_(2)O_(4)nanocomposite.At lower frequencies the values of dielectric constant is maximum for pure CoFe_(2)O_(4)nanoparticles.
基金the UGC,New Delhi,for fnancial support through the fund No.37-256/2009 (SR)
文摘ZnO nanoparticles of different sizes were prepared by varying the molar ratio of glycine and zinc nitrate hexahydrate as fuel and oxidizer （0.1, 0.8, 1.11, 1.3, 1.5, 1.7, 2.0） by simple solution combustion method. UV-Visible spectrophotometry studies show that, the band gap of the prepared ZnO nanoparticles increases with increasing fuel to oxidant （F/O） molar ratio up to 1.7 revealing the formation of ZnO nanoparticles. The decrease in band gap for the sample of F/O molar ratio 2.0 is due to an increase in particle size. Powder X-ray diffraction patterns of the prepared samples show the formation of single phase ZnO nanoparticles and the particle size decreases with increasing F/O molar ratio up to 1.7. Surface morphology of the prepared samples was studied by scanning electron microscopy and it was observed that, the porosity increases with increasing F/O molar ratio. DC electrical conductivity at room temperature and in the temperature range of 303-563 K was studied for all the samples and the results revealed that, the sample of F/O molar ratio 1.7 has low electrical conductivity at room temperature and high EAR （high temperature activation energy） compared to other samples.
