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Nanoscience and Nanotechnology - Volume:12 Issue: 3, Summer 2016

International Journal Of Nanoscience and Nanotechnology
Volume:12 Issue: 3, Summer 2016

  • تاریخ انتشار: 1395/07/26
  • تعداد عناوین: 7
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  • S. Alamolhoda, S. M. Mirkazemi *, N. Benvidi, T. Shahjooyi Pages 131-137
    In this research nanoparticles of Ni0.55Zn0.35Cu0.1Fe2O4 were synthesized by sol–gel auto-combustion method. Changes in phase constituents, microstructure and magnetic properties as a result of Zn and Cu additions were evaluated by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), and Vibration Sample Magnetometer (VSM) techniques. XRD results show that the doped sample have a single phase cubic spinel structure while the undoped sample consists of NiFe2O4, FeNi3, α-Fe2O3 and NiO phases. Changes in cell parameter calculated by MAUD software using XRD patterns showed that the cell parameters of the doped sample had expansion about 0.044 Å. Microstructural studies demonstrated considerable reduction of particle size and particle size distribution in the sample synthesized with dopants. Magnetic measurements have been determined increasing of the saturation magnetization from 36.96emu/g to 56.46emu/g and decreasing of coercivity force from 175.5Oe to 98.79Oe in the sample synthesized with dopants. Changes in microstructure and magnetic properties have been explained.
    Keywords: Nickel ferrite, Sol, gel auto, combustion, Magnetic properties, Dopants, Nanoparticles
  • A. R. Khorshidi *, Sh. Shariati Pages 139-147
    Mesoporous MCM-41 was coated on Fe3O4 nanoparticles and then functionalized with sulfurochloridic acid to provide a core-shell solid acid nano-catalyst. The catalyst was characterized by transmission electron microscopy (TEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), Brunauer-Emmet-Teller analysis (BET) and vibrating sample magnetometery (VSM). The obtained nano-sized magnetic catalyst was used in three-component reaction of indoles, phenylglyoxal monohydrate and N-arylenaminones to furnish the desired 3,2′- bisindoles in good yields under mild reaction conditions. In order to evaluate reusability of the catalyst, the reaction of indole, phenylglyoxal monohydrate and 5,5-dimethyl-3-(phenylamino)cyclohex-2-enone was carried out in the presence of the recycled catalyst in successive runs. From reaction run 1 to 5, the yields were 89%, 89%, 81%, 75% and 63%, respectively. Therefore after five runs, 26% decrease in the efficiency of the catalyst system was observed. In order to confirm heterogeneity of the catalyst, the amount of sulfonic acid loading was determined for the recycled catalyst of the 3rd run and a similar result (2.40 mmol SO3H/g) was obtained, which confirmed that no considerable leaching was occurred during the course of reaction.
    Keywords: 3, 2? bisindole, Core, shell, Heterogeneous, Solid acid, Catalyst
  • M. Habibnejad Korayem* Pages 149-166
    The sensitivity analysis of atomic force microscope (AFM) based manipulation of gold spherical nanoparticles in air medium has been carried out in previous research works. In the AFM-based manipulations conducted in various biological liquid mediums, the new environmental parameters associated with these biological fluids also affect the dynamics of the manipulation process. Therefore in this research, the Sobol sensitivity analysis method has been employed to find out how these new parameters as well as the other effective parameters influence the manipulation process. The parameters have been classified into two groups of AFM parameters and environmental parameters. According to the obtained simulation results, in the group of AFM parameters, cantilever thickness (with a sensitivity index of 57%) is the most sensitive parameter in the manipulation of cylindrical biological micro/nanoparticles, followed by the parameters of cantilever length and cantilever width. By examining the sensitivity of environmental parameters for cylindrical biological micro/nanoparticles in biological mediums, it is observed that the highest sensitivity belongs to the dimensional parameters of target particles (the most sensitive environmental parameter is cross-sectional radius of target particle with a sensitivity index of 52%), followed by the sensitivity of adhesion work in the biological medium of manipulation. It is found that the critical force for the onset of movement increases substantially with the increase in the cross-sectional radius of target particle, ratio of particle length to its cross-sectional radius and also with the increase in the work of adhesion in the biological environment.
    Keywords: sensitivity analysis, Biomanipulation, Atomic force microscopy, Different biological mediums, Cylindrical biological particles
  • R. Layeghi, M. Farbodi *, N. Ghalebsaz, Jeddi Pages 167-174
    In this research, firstly polyaniline-zinc oxide (PANI-ZnO) nanocomposite was successfully synthesized by chemical polymerization of aniline in the presence of ZnO nanoparticles and then, 5%, 10% and 15% solutions of PANI–ZnO nanocomposites were mixed with a solution of polystyrene (PS) in tetrahydrofurane (THF) and PANI-PS-ZnO nanocomposites were obtained. The prepared nanocomposites were used as coating on iron coupons by solution casting method and their anti corrosive performance were studied by open circuit potential (OCP) and Tafel techniques in 3.5% NaCl solution as corrosive environment. The obtained results showed that the coating of PS-[PANI-ZnO 10%] nanocomposite had superior corrosion protection effect on iron sample compared to that of pure PANI, PANI–ZnO nanocomposite, PANI-PS composite and two other PANI-PS-ZnO nanocomposite coatings. Cyclic voltammetry (CV) studies showed that the prepared PS-[PANI-ZnO 10%] nanocomposite was electroactive and this property was reversible and stable. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques were used to characterize the composition and structure of PS-[PANI-ZnO 10%] nanocomposite. To study thermal stability of PS- [PANI-ZnO 10%] nanocomposite, thermogravimetric analysis (TGA) was used.
    Keywords: Corrosion, Nanocomposite, Polyaniline, Polystyrene, ZnO nanoparticle
  • M. Kurian*, B. Varghese, T. S. Athira, S. Krishna Pages 175-181
    Silver particles of nanometric size were prepared from silver sulphate solution using Curcuma Longa and Zingiber Officinale rhizome extracts. The reaction was completed at 3 hours on using Curcuma Longa rhizome extract as reducing agent, making it one of the fastest biosynthesis route reported so far. The plasmon bands at 420 nm in the UV visible spectra are broad with an absorption tail in the longer wavelengths, which could be due to the size distribution of the particles. TEM images indicated the presence of silver nanoparticles in the range of 20-50 nm. FTIR spectra suggest that the biological molecules possibly perform dual functions of formation and stabilization of silver nanoparticles in the aqueous medium. Silver NPs produced from 5mM silver salt solutions showed greatest antibacterial activity against Staphylococcus aureus pathogen (gram positive).
    Keywords: Biosynthesis, Silver nanoparticles, Curcuma longa, Zingiber officinale
  • S. Zeinali*, S. Nasirimoghaddam, S. Sabbaghi Pages 183-190
    Iron oxide (Fe3O4) nanoparticles with average sizes of 10 nm were synthesized by a chemical coprecipitation method in the presence of chitosan. Chitosan as a natural polymer which can be extracted from crustaceans was used in the synthesis process in order to achieve more dispersed nanoparticles. Also, chitosan was used to obtain functionalized magnetic nanoparticles for using in different area of research. Chitosan should be first carboxymethylated and then covalently bounded onto the surface of Fe3O4 nanoparticles via carbodiimide activation. Because of size – dependent different property of nanoparticles, The effects of the carboxymethyl chitosan concentration, sonication time and the reaction temperature in the synthesis procedure of chitosan-bound Fe3O4 nanoparticles were investigated and then the best condition used for final product. Dynamic light scattering were used to investigate the effect of each experimental parameters on the size and size distribution of prepared nanoparticles. Transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-Vis and FT-IR spectroscopy, vibrational sample magnetometer (VSM) and zeta-potential methods were carried out on the final productin order to characterize the size, size distribution, magnetic property and surface charge of as-prepared nanoparticles.
    Keywords: Chitosan, Magnetic nanoparticles, Synthesis
  • M. Soleimani *, M. Ghorbani, S. Salahi Pages 191-197
    Polypyrrole-chitosan nanocomposite (PPy-CTN) was synthesized by dispersion polymerization of PPy in presence of CTN. Preparation of spherical PPy nanoparticles that were successfully covered with a thin layer of chitosan was confirm by transmission electron microscopy (TEM) technique. Characterization techniques also revealed the presence of CNT in the polymer matrix and its presence was confirmed by the shift of absorption band in fourier transform infrared spectroscopy (FTIR). The prepared polymer was then tested for the antibacterial properties against Gram-negative bacteria; Escherichia coli (E. coli) bacteria. The antibacterial property was assessed by disk diffusion method. The results showed clearly that, PPy-CTN nanocomposite strongly inhibit the growth of wild-type E. coli (20 ± 0.5 mm) followed by PPy (11 ± 0.5 mm) and CTN (2 ± 0.5 mm). The PPy-CTN nanocomposite exhibits a significant enhancement in antibacterial activity better than that of pristine PPy and CTN. In particular mechanisms of antibacterial action in PPy-CTN nanocomposite were discussed.
    Keywords: Polypyrrole, Chitosan, Antibacterial mechanism, Escherichia coli