فهرست مطالب

Nano Structures - Volume:5 Issue: 2, 2015
  • Volume:5 Issue: 2, 2015
  • تاریخ انتشار: 1394/05/28
  • تعداد عناوین: 14
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  • M. Zahraei, A. Monshi, D. Shahbazi-Gahrouei, M. Amirnasr, B. Behdadfar, M. Rostami Pages 77-86
    Manganese zinc ferrite nanoparticles (MZF NPs) were synthesized by using a direct, efficient and environmental friendly hydrothermal method. To improve the colloidal stability of MZF NPs for biomedical applications, NPs were coated with chitosan by ionic gelation technique using sodium tripolyphosphate (TPP) as crosslinker. The synthesized NPs were characterized by X ray diffraction (XRD) analysis, inductively coupled plasma optical emission spectrometry (ICP-OES), fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and the dynamic light scattering (DLS) methods. The results confirmed the spinel ferrite phase formation without any calcination process after synthesis. Mean particle size of bare NPs was around 14 nm. Moreover, certain molar ratio of chitosan to TPP was required for encapsulation of NPs in chitosan. Coated NPs showed hydrodynamic size of 300 nm and polydispersity index about 0.3.
    Keywords: Mn, Zn ferrite nanoparticles, Hydrothermal, Chitosan, Ionic gelation, MRI contrast agents
  • F. Shahi, M. Akbarzadeh Pasha, A. A. Hosseini, Z. S. Arabshahi Pages 87-95
    Nanometric Carbid Silicon (SiC) supported monometallic and bimetallic catalysts containing Fe, Co, Ni transition metals were prepared by wet impregnation method. Multiwall carbon nanotubes (MWCNTs) were synthesized over the prepared catalysts from catalytic decomposition of acetylene at 850°C by thermal chemical vapor deposition (TCVD) technique. The synthesized nanomaterials (catalysts and CNTs) were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Raman spectroscopy. In this paper, using of nanometric SiC powder as catalyst support was examined and the effect of applied catalyst type on characteristics of grown CNTs was investigated. The results revealed that iron, cobalt and nickel are in oxide, cobalt ferrite (CoFe2O4) and nickel ferrite (NiFe2O4) forms and nanometric SiC powder can be applied as an appropriate catalyst support in CNT growth process. It was observed that the produced CNTs on bimetallic Fe-Co possess smaller average diameter, less amorphous carbon and denser morphology compared to other binary metallic combinations. It was found that the catalytic activity of bimetallic composition decreased in the order of Fe-Co> Fe-Ni> Co-Ni. Furthermore, the monometallic Fe catalyst has the most catalytic activity compared to monometallic Co and Ni catalysts.
    Keywords: MWCNTs, TCVD, Wet impregnation, Nanometric SiC, Monometallic catalyst, Bimetallic catalyst
  • M. Ahmadzadeh, M. Almasi-Kashi, A. Ramazani Pages 97-104
    CoFe/Cu multilayer nanowires were electrodeposited into anodic aluminum oxide templates prepared by a two-step mild anodization method, using the single-bath technique. Nanowires with 30 nm diameter and the definite lengths were obtained. The effect of CoFe layers thickness and annealing on the magnetic behavior of the multilayer nanowires was investigated. The layers thickness was controlled through the pulses numbers: 200, 260, 310,360 and 410 pulses were used to deposit the CoFe layers, while 300 pulse for the Cu layers. A certain increase in coercivity and squareness of CoFe/Cu multilayer nanowires observed with increasing the CoFe layer thickness and annealing improved the coercivity and decrease squareness of CoFe/Cu multilayer nanowires. First order reversal curves after annealed showed amount domains with soft magnetic phase, it also shows decreasing spreading of distribution function along the axis after annealed
    Keywords: Multilayer nanowire, Annealing, Coercivity, Magnetic properties
  • M. Ghorbanpour Pages 105-110
    The Silver SPR chip was modified by alkaline-silane condensation with aminopropyltriethoxysilane (APTES) in NaOH aqueous solution at different times. Silver sputtered slides coated with APTES were immersed in NaOH solution, enabling us to produce silver surfaces homogeneously covered with APTES. The surface properties of grafted APTES on sputtered silver surface as a occasion of time were studied using SPR analysis, AFM and contact angle measurement. The mechanical and chemical stability of samples was assayed by tape test and NaCl test. The answers show that hydrolysis and condensation of APTES are activated in alkaline solution and lead to formation of a protective APTES layer on the surface of silver. The morphology of APTES on silver surface is a function of coverage density that is altered by changing time. At short times (< 30 min), APTES molecules physically adsorb to the surface leads to weak protection. At higher condensation times, APTES molecules chemically bond to the surface and each other leads to better protection.
    Keywords: Surface plasmon resonance, Stability, Aminopropyltriethoxysilane, Condensation
  • M. Goudarzi, D. Ghanbari, M. Salavati-Niasari Pages 110-115
    Al(OH)3 nanoparticles were synthesized by a simple precipitation reaction. The effect of various amines like ethylene diamine, propylene diamine, triethylenetetramine and tetraethylenepentamine as precipitating agents on the morphology of Al(OH)3 nanostructures was investigated. The influence of Al(OH)3 nanoparticles on the flame retardancy of the poly vinyl alcohol (PVA) matrix was studied using UL-94. Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. Flame retardancy of the nanocomposites enhanced in the presence of Al(OH)3 nanostructures. This improvement of nanocomposites is due to the endothermic decomposition of Al(OH)3 and release of water which dilutes combustible gases.
    Keywords: Al(OH)3, Nanoparticles, Nanocomposite, Poly vinyl alcohol
  • M. Shahrekizad, A. Gholamalizadeh Ahangar, N. Mir Pages 117-127
    In this study, a set of experiments were conducted to investigate the influence of EDTA-grafted iron oxide nanoparticles exposure on agronomic traits of sunflower (Helianthus annuus) plants. The experiment was implemented by applying Nano-Fe3O4-EDTA and Fe-EDTA fertilizers applied through spray or soil amendment. A variety of parameters including Aerial organ biomass, Number of leaves, Plant height, Chlorophyll content as well as elemental quantities of the plants were investigated. The results demonstrated considerably dominant effect of Nano-Fe3O4-EDTA fertilizer on many of the studied factors. The dramatically increased Fe content of plants (137% relative to the control) by using nano-Fe-EDTA, makes this novel fertilizer a promising candidate to obviate iron deficiency problem in plants. Moreover, it was clearly observed that more pronounced positive effects is obtained through soil amendment than by foliar application of fertilizers and only in some cases such as aerial organ biomasses and Fe content, the foliar treatment has turned out to be more effective.
    Keywords: Agronomic traits, Biocompatible nanoparticles, Coated nanoparticles, Iron deficiency, Nanobiotechnology
  • M. Najafi, H. Haratizadeh, M. Ghezellou Pages 129-135
    In this study un-doped and Eu-doped ZnO nanorods and microrads were fabricated by Chemical Vapor Deposition (CVD) method. The effects of annealing, synthesis temperature and structure on structural and photoluminescence properties of Eu-doped ZnO samples were studied in detail. Prepared samples were characterized using X-Ray diffraction (XRD), scanning electron microscopy (SEM), particle size analysis (PSA) and Photoluminescence Spectroscopy (PL) analysis. XRD results indicated that all of samples have a wurtzite structure and Eu3+ ions were incorporated successfully into the lattice of ZnO nanostructures. SEM and PSA analysis exhibit nanorads rather than microrads samples have a more surface to volume ratio which cause to enhance surface defects. This study recommends that energy transfer (ET) from ZnO host to Eu ions via intrinsic defects at indirect excitation. By annealing due to decease of intrinsic defects particularly oxygen vacancy ET and consequently Eu ions emissions are decreased considerably. Pl analysis exhibit relative intensities of the electric-dipole and magnetic-dipole transitions were changed in different growth conditions.
    Keywords: ZnO, CVD, Photoluminescence, Nanorod
  • S. Zinatloo-Ajabshir, N. Taheri Qazvini Pages 137-144
    In our previous work, the effect of use of a water soluble CDI/NHS system as nontoxic cross-linking agent on fabrication of gelatin nanoparticles was investigated. In this research, the effect of variation in some synthetic parameters of gelatin nanoparticles cross-linked by CDI/NHS system such as type of gelatin and formulation of cross- linking agent on their size and distribution was examined. The conventional two step desolvation method was used for preparation of gelatin nanoparticles. The morphology, mean size and size distribution of the formed nanoparticles were evaluated and compared with each other. In addition, intrinsic viscosities of all the nanoparticles were measured and compared under different conditions. The results showed that the presence of more NHS and absence of NHS catalyst in CDI/NHS system lead to the large particle size and broad size distribution of nanoparticles that were attributed to the fast and slow cross-linking rate, respectively.
    Keywords: Gelatin, Nanoparticles, Water soluble carbodiimide, Cross, linking agent, Intrinsic viscosity
  • A. Rahdar, M. Aliahmad, Y. Azizi Pages 145-151
    In the current paper,Nanostructured Nickel oxide (NiO) were synthesized by co-precipitation method using Nickel(II) Chloride Hexahydrate (NiCl2.6H2O) and sodium hydroxide (NaOH) as starting material. Structural, optical and magnetic properties of nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Atomic force microscope (AFM), UV–Vis absorption; Fourier transformed infrared (FTIR) and vibrating sample magnetometer (VSM) technique. The X-ray diffraction pattern studies revealed the NiO have a face-centered cubic (FCC) structure and confirmed the presence of high degree of crystallinity nature NiO nanoparticles that their average size is found to be 26 nm. The composition of nanostructures confirmed by analysis of FTIR spectra. The average size of the NiO nanoparticle observed from scanning electron microscopy images is found to be dimensions about 24 nm. Magnetic measurement confirmed the Nickel Oxide nanostructures superparamagnetic behavior at room temperature (RT) after calcinations.
    Keywords: Precipitation method, NiO:Cu nanoparticles, Hysteresis loop, VSM
  • J. Safaei-Ghomi, S. Zahedi, M. Javid, M. A. Ghasemzadeh Pages 153-160
    This work described one pot syntheses of polysubstituted 2,6- dicyanoaniline and 2-(3-Oxo-1,3-diarylpropyl) malononitrile derivatives in the presence of MgO nanoparticles (NPs) under grinding conditions and microwave irradiation, respectively. The simple experimental procedure includes shorter reaction times, higher yields, lower cost and environmental friendliness. Other remarkable features are reusability of catalyst, MgO NPs can be reused at least five times without any obvious change in its catalytic activity.
    Keywords: Heterogeneous catalyst, Nanostructures, Heterocycles, Synthetic methods, Cyclization, MgO nanoparticles
  • A. Ghozatloo, S. Azimi Maleki, M. Shariaty-Niassar, A. Morad Rashidi Pages 161-168
    This article presents an experimental investigation on effects of morphology of nanoparticles on the viscosity nanofluids (NFs). Water and ethylene glycol were used as base fluids. A two step method was used for preparation of NFs. SiO2 nanoparticles, CNT and graphene nano sheets were dispersed in the base fluids separately with the volume fraction ranging from 0.05% to 1.5%. Stability of the nanoparticles was established by adding adequate surfactant and sonication enough time. Then viscosity of the NFs was measured by Brookfield viscometer at fix ambient temperature. First, it has been concluded that, viscosity of NFs increases significantly with increasing of nanoparticle volume fraction. Then the results of theoretical models (Einstein, Brinkman, Batchelor and Wang) were compared with experimental data and the deviation of theme was calculated. In order to reduce of this deviation, a correlation was developed based on the geometry of nanoparticles. The modified models showed reasonably better agreement with the experimental results.
    Keywords: Morphology, Viscosity, Nanofluid, CNT, Graphene
  • S. Moshtaghi, M. Salavati-Niasari, D. Ghanbari Pages 169-174
    In this paper, calcium stannate nanoparticles were synthesized by a fast and simple co-precipitation procedure. For CaSnO3 preparation ammonia was used as precipitation agent. The effect of various surfactants such as cationic, anionic and neutral on the morphology of the products was investigated. By changing in Ca(Sal)2 as a new precursor different morphologies were obtained. Ligand as a capping agent with steric hindrance leads to preparation of product with lower particle size. These semiconductor nanostructures have photo-catalyst activities and can degrade organic dyes as water pollution. The synthesized materials were characterized by X-ray diffraction (XRD) technique, scanning electron microscopy (SEM) Fourier transform infrared (FT-IR) and UV-visible spectroscopy.
    Keywords: CaSnO3, Nanoparticles, Photo, catalyst
  • M. Ghorbanali, A. Mohammadi, R. Jalajerdi Pages 175-181
    Mg(OH)2 nanoparticles were synthesized by a rapid microwave reaction. The effect of sodium dodecyl sulfonate (SDS as anionic surfactant) and cetyl tri-methyl ammonium bromide (CTAB as cationic surfactant) on the morphology of magnesium hydroxide nanostructures was investigated. Multi wall carbon nano tubes was organo-modified for better dispersion in cellulose acetate matrix. The influence of Mg(OH)2 nanoparticles and modified multi wall carbon nano tubes (MWCNT) on the thermal stability of the cellulose acetate (CA) matrix was studied using thermo-gravimetric analysis (TGA). Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. Thermal decomposition of the nanocomposites shift towards higher temperature in the presence of Mg(OH)2 nanostructures. The enhancement of thermal stability of nanocomposites is due to the endothermic decomposition of Mg(OH)2 and release of water which dilutes combustible gases.
    Keywords: Nanoparticles, Nanocomposite, Thermal Stability, Cellulose Acetate
  • M. Behpour, M. Mehrzad, S. M. Hosseinpour, Mashkani Pages 183-187
    In this research, the thin films of N-S doped titanium dioxide (TiO2) were successfully prepared by simple sol-gel method in the presence of tetrabutylorthotitanate as a starting reagent. Furthermore, titanium dioxide (TiO2) was functionalized with thiourea. Furthermore, N-S doped titanium dioxides (NSTO) were fixed on glass balls by glass balls fixed-bed reactor system. Besides, the effect of some parameters such as volume and exit flow rate of basic yellow 28 solution on the degradation of basic yellow 28 solution under visible light irradiation were investigated. Moreover, the degradation rates were found to be strongly influenced by all the above parameters. The as- synthesized N-S doped titanium dioxides (NSTO) were characterized by X-ray diffraction (XRD), scanning Electron Microscopy (SEM), spectra energy dispersive analysis of X-ray (EDX), and ultraviolet–visible (UV–Vis) techniques.Sol-gel synthesis of titanium dioxide was favorable, because the synthesis time of sol-gel method was shorter than that of other method.
    Keywords: NSTO, Semiconductor, Basicyellow28, Photodegradation, Sol, gel