Nadia Abdel Aal

Novel rapid synthesis of zinc oxide nanotubes via hydrothermal technique and antibacterial properties.

ZnO nanotubes with the wurtzite structure have been successfully synthesized via simple hydrothermal solution route using zinc nitrate, urea and KOH for the first time. The structural, compositions and morphology architectures of the as synthesized ZnO nanotubes was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and high resolution transmission scanning electron microscopy (HRTEM). TEM showed that ZnO nanotubes exhibited a wall thickness of less than 2 nm, with an average diameter of 17 nm and the length is 2 μm. In addition, the antibacterial activity of ZnO nanotubes was carried out in vitro against two kinds of bacteria: gram - negative bacteria (G -ve) i.e. Escherichia coli (E. coli) and gram - positive bacteria (G +ve) i.e. Staphylococcus aureus. Therefore, this work demonstrates that simply synthesized ZnO nanotubes have excellent potencies, being ideal antibacterial agents for many biomedical applications.

New Functional Conductive Polymer Composites Containing Nickel Coated Carbon Black Reinforced Phenolic Resin

The network structure of Ni-coated carbon black (NCB) composites filled with phenolic resin was investigated by means of using scanning electron microscopy, viscosity, interfacial tension, shrinkability, Flory-Huggins interaction parameters, and swelling index. The electrical properties of the composites have been characterized by measurement of the specific conductivity as a function of temperature. Additionally, the variation of conductivity with temperature for the composites has been reported and analyzed in terms of the dilution volume fraction, relative volume expansion, and barrier heights energy. The thermal stability of phenolic-NCB composites has been also studied by means of the voltage cycle processes. The experimental data of EMI wave shielding were analyzed and compared with theoretical calculations. The mechanical properties such as tensile strength, tensile modulus, hardness and elongation at break (EB) of NCB-phenolic resin composites were also investigated.

Improving the optical and electrical properties of Zinc Oxide thin film by Cupric Oxide dopant

Abstract : ZnO and ZnO/CuO nanocomposite were successfully synthesized by Sol-Gel technique. The crystal structure was investigated by X- ray diffraction technique and the molecular structure was studied by Fourier transformation infrared. Atomic force microscopy was used to study the topological properties of the prepared thin films. The optical properties were studied and the optical band gap were evaluated from the x-axis intercepts at (αhυ) 2 =0 and found to be decreased from 3.27 to 3.26 eV as the dopant increased. ZnO and ZnO/CuO nanocomposite were used as interfacial layer on schottky diode. The technical parameters such as ideality factor and the barrier height were found to be increased from 3.7 to 6.5 and from 0.59 to 0.62 eV respectively as the dopant were increased. Keywords: ZnO; CuO; Composite; optical Properties; Schottky diode; I. Introduction Nanostructured metal-oxide semiconductor materials have been widely studied due to their electronic, optical, optoelectronic properties and potential applications in nanoscale devices. These materials offer many new opportunities to study fundamental surface processes in a controlled manner and this, in turn, leads to fabrication of new devices. Great interest has been shown in the preparation of nanomaterials, particularly oxides. Transparent conductive oxides (TCOs) such as Zinc Oxide (ZnO), Cadmium Oxide (CdO), Tin Oxide (SnO

New non-linear electrical-thermal switching of carbon nanoparticles/silane coupling agent reinforced phenolic resin nanocomposites

This paper evaluates the use of a new multifunctional conducting polymer containing phenolic resin reinforced by carbon black (CB) nanoparticles modified by silane coupling agent to produce positive temperature coefficient (PTC) thermistors and switching current. The percolation threshold of the conducting composites at room temperature was found to be as low as 4 wt% of CB. Temperature dependent electrical characterisation of phenolic resin/CB nanocomposites is performed. The composites exhibit PTC properties with ρmax/ρmin value as great as 104. Electrical parameters such as charge carriers type, drift mobility, concentration of charge carriers, activation and hopping energy are verified with CB content. The current-voltage curves of the nanocomposites change from linear to non-linear behaviour and the switching current is observed within the non-linear regime.

Preparation, characterisation and optical properties of zinc oxide nanoparticles obtained by new intercalation chemical route

A new simple intercalation chemical route was used to synthesise ZnO nanoparticles via ZnO, sodium doclecyl sulfate as a surfactant and hydrogen peroxide at 90°C with strong stirring for five hours. The results of X-ray diffraction (XRD) and Fourier transformer infrared spectroscopy (FTIR) show that ZnO nanoparticles are all of crystalline hexagonal zincite phase. The results of scanning electron microscopy (SEM) and XRD indicate that the mean sizes of ZnO nanoparticles is about 25 nm. The thermal gravimetry reveals that the as-prepared ZnO has good thermal stability. Compared with other synthesis approaches, the proposed method can get fairly good product with a relatively low cost. The optical band gap energy of ZnO was 3.17 eV.