V. Senthil Kumar

Zinc oxide nanoparticles reinforced conducting poly(aniline-co- p-phenylenediamine) nanocomposite

Zinc oxide (ZnO) nanoparticles were synthesized by thermal decomposition method and formation of composite with conducting copolymer via in situ chemical oxidative polymerization. Transmission electron microscopy showed that the nanoparticles with an average diameter of 15–25 nm were dispersed in the copolymer matrix. The comonomer molecules were adsorbed on the surface of ZnO particles and then polymerized to form core–shell nanocomposite. The obtained nanocomposite showed a significant improvement in the thermal behavior as indicated by thermogravimetric analysis. The nanocomposite was also confirmed by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, and X-ray diffraction. Room temperature conductivity of nanocomposite was higher than the value obtained for the pure copolymer. Photocatalytic activity of the nanocomposite was evaluated by measuring the degradation of methylene blue dye under UV irradiation.

Poly(aniline-co-o-toluidine) Encapsulated Zinc Oxide Nanocomposite: Preparation, Characterization, and Photocatalytic Reduction of Cr(VI)

Poly(aniline-co-o-toluidine) encapsulated zinc oxide (ZnO) nanocomposite was prepared by chemical oxidative polymerization. The composition, morphology and structure of poly(Ani-co-oT)/ZnO nanocomposite were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and UV-visible spectroscopy (UV-vis). FTIR spectrum endorsed the formation of nanocomposite. TEM image showed that the ZnO nanoparticles were well dispersed in the copolymer matrix. XRD results revealed that the crystallinity of copolymer was more pronounced after the addition of ZnO. TGA results illustrated that the decomposition temperature of nanocomposite was higher than the pure copolymer. Electrical conductivity of the copolymer was increased by the addition ZnO. In addition, the photocatalytic reaction with illuminated nanocomposite can be effectively applied to treat wastewater contaminated with Cr(VI). The reduction pattern of Cr(VI) was better fit to first-order kinetic model. The nanocomposite was also applied as a photocatalyst for the degradation of methylene blue (MB) dye.

Conducting Copolymer/ZnO Nanocomposite: Synthesis, Characterization, and Its Photocatalytic Activity for the Removal of Pollutants

The authors describe the synthesis of hybrid nanocomposites composed of electrically conducting poly(aniline-co-o-aminophenol) [poly(Ani-co-oAP)] copolymer and zinc oxide (ZnO) by in situ chemical oxidative polymerization. The nanoparticles were used as cores in the formation of nanocomposites. Transmission electron microscopy revealed nanoparticles with a mean diameter of 15–25 nm were dispersed in the copolymer matrix. Fourier transform infrared spectroscopy confirmed the formation of nanocomposites. Thermogravimetric analysis indicated that the nanocomposite had a higher decomposition temperature than the pure copolymer. UV-vis spectrum of the diluted colloidal dispersion of nanocomposite was similar to those of the pure copolymer. X-ray diffraction showed that the copolymer was crystalline in nature and the crystallinity was unaffected by the addition of ZnO. The room-temperature conductivity of the copolymer increased with the addition of ZnO. The nanocomposite was applied as a photocatalyst for methylene blue (MB) degradation. The result revealed substantial degradation of the MB dye (∼88%) under UV-light illumination. The photodegradation of MB dye was fitted to first-order kinetic model.

Investigation on Optical Properties of CuS and Zn Doped CuS Thin Films by Chemical Bath Deposition Method

For decades copper sulfide has been considered as the most superior optical and semiconductor material. An attempt has been made to prepare bare and Zn doped CuS thinfilms by simple chemical bath deposition method. The prepared samples were characterized by XRD, UV and PL to identify and study its structural and optical properties. Results of XRD analysis confirmed the formation of CuS of Covellite phase. Optical properties were studied and the material exhibits a band gap of 2.41 eV and 2.39 eV for pure and Zn doped samples respectively.

Influence of Annealing Temperature on Nanocrystalline ZnO Thin Films Prepared by Sol-Gel Dip Coating Method

ZnO nanocrystalline thin films have been prepared on glass substrates by sol-gel dip coating method. The ZnO thin films have been coated at room temperature for the pH value of 10 and annealed at 300°, 400° and 500°C respectively. The X- ray diffraction pattern shows that ZnO nanocrystalline thin films are of hexagonal structure and the grain size is found to be in the range of 25-45 nm. Scanning electron microscope images show that the surface morphology improves with increase of annealing temperature. The TEM analysis reveals the formation of ZnO nanocrystalline with an average grain size of 44 nm. The compositional analysis results show that Zn and O are present in the sample. The optical studies shows that the films are highly transparent and exhibit a direct band gap. The band gap has been found to lie in the range of 3.07 to 3.32 nm depending on the annealed temperature suggesting the formation of ZnO nanocrystalline thin films.