JOURNAL OF NANOSTRUCTURES
Year:2014 | Volume:4 | Issue:3|Papers Count:15

Nanoparticles of coordination polymer [Co2 (pydc) 2 (H2O) 6] n.2n H2O [H2pydc=pyridine-2, 5-dicarboxylic acid] have been synthesized by sonochemical method and characterized by elemental analysis, infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, DLS particle size analysis and TGA/DTA. The structure of single crystalline coordination polymer developed from nanosized coordination polymer was determined by X-ray crystallography. The XRPD studies reveal that nanoparticles of coordination polymer [Co2 (pydc) 2 (H2O) 6] n.2nH2O have same structure as that of bulk single crystalline polymer. The coordination polymer posses a 1-D chain like extended structure with binuclear cobalt (II) nodal unit. The coordination geometry around two cobalt atom Co (1) and Co (2) can be described as slightly distorted octahedron. The average particle size of nanoparticles calculated by using least square method of Modified Scherrer formula was found ~27 nm. The nanoparticles are composed of polyhedral blocks with definite edges. Dynamic Light Scattering (DLS) measurements show a narrow size distribution. The nanoparticles are thermally stable up to 352 K and thereafter decompose in well defined steps.

Carbon nanotubes were synthesized over a series of Zn-containing Fe/alumina catalysts by chemical vapor deposition method at two reaction temperatures of 850 and 950 °C using methane as a carbon source. Catalysts were synthesized by keeping Fe concentration constant and varying Zn concentration to study the effects of Zn.The catalysts were characterized using X- ray powder diffraction and N2 adsorption – desorption methods which confirmed the successful synthesis of catalysts and metals particles were inserted in alumina pores. The synthesized Carbon nanotubes were tested by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry analysis (TGA) and Raman spectroscopy. SEM images showed that the diameter of nanotubes almost was decreased with increasing Zn content of catalysts. In Raman spectroscopy, two main bands related to the carbon nanotubes were observed. Further, TGA results revealed that the percent of synthesized carbon nanotubes were almost increased with increasing [Zn] / [Fe] proportions.

In this research, gelatin nanoparticles were synthesized via inverse miniemulsion method by employing a mixture of a water soluble carbodiimide (CDI) and N-hydroxysuccinimide (NHS) as a non-toxic cross-linking system. The gelatin nanoparticles were characterized for their size and size distribution, morphology and stability and were compared with those of nanoparticles cross-linked by glutaraldehyde (GA) as the most commonly utilized cross-linking agent. The results showed the formation of more homogeneous nanoparticles with smaller size when CDI/NHS used as cross-linking agent under the same synthesis condition. Moreover, dilute solution viscosimetry experiments confirmed the stability of the nanoparticles under various physicochemical conditions. The differences in the characteristics of CDI/NHS and GA cross-linked nanoparticles were ascribed to the different nature of network formation using the two cross-linking agents. Generally, these results suggested CDI/NHS cross-linked gelatin nanoprticles as an interesting candidate for drug delivery application.

A straightforward approach for the extraction of the quercetin was carried out by a nanoporous molecularly imprinted acrylic acid-based network copolymer as asolid sorbent. This technique involves a molecular template (quercetin) which is surrounded by functional monomers and are subsequently co-polymerized in the presence of an excess of the cross linkers. In this process, three-dimensional binding sites are generated that are complementary to the quercetin template in terms of size, shape and position of functional groups. After removal of the imprinting quercetin template, the nanostructured polymer can therefore specifically recognize and re-bind the same or structurally very similar molecules. The synthesized MIP by bulk polymerization was exhibited a good tendency to absorb the quercetin template in a solid phase extraction (SPE) system.The prepared MIP achieved a binding capacity of 169 mg/grfor the quercetin in acetonitrile-water (1: 1 v/v) solvent.Imaging by scanning electron microscope (SEM) was carried out to determine the surface morphology of the prepared MIP.

In this research an effective and appropriate method has been developed for one-pot synthesis of newN -phenyl fulleroisoxazoline using Fe3O4@SiO2 nanoparticles as a green magnetically recyclable catalyst. The prepared catalytic samples were characterized by XRD, SEM, FT-IR and VSM. The products have been characterized by physical and spectroscopic data such as IR, 1H NMR, 13C NMR, and MS analyses.

Carbon Spheres were fabricated by hydrothermal method and their structural properties were investigated. Carbon Spheres with average sizes around of 230, 320 and 430 nm were synthesized in different concentration of glucose aqueous solution and different hydrothermal reaction time. The temperature of 180oC by a hydrothermal reaction was fixed in all of glucose concentration and hydrothermal reaction time. The result showed that the spherical shape of Carbon Spheres was formed in the special concentration of glucose aqueous solution and hydrothermal reaction time.The product obtained was characterized by X-ray diffraction (XRD); Fourier transforms infrared (FTIR) spectra, which have inferred the Carbonic nature of the product. Further, SEM images have revealed the spheres having quite spherical morphology.

We design a novel nano-ring resonator using two-dimensional photonic crystal (2D-PhC), for bio-sensing applications. The structure of biosensor is created by two-curve-shaped ring resonator which sandwiched by two waveguides. These are configured by removing one row of air holes. The refractive index of sensing hole is changed by binding an analyte. Hence, intensity of the transmission spectrum shifts to lower value. This process is utilized for determining the properties of the analyte. The quality factor is obtained about 1550 and for a unit change in the refractive index of sensing hole, the intensity of transmission spectrum reduces as 4.125 units.

An efficient and environmentally benign method for the synthesis of aryl iodides have been developed by diazotization of aromatic amines with NaNO2 and nanosilica periodic acid (nano-SPIA) as a green catalyst via grinding followed by a sandmeyer iodination by KI under solvent-free conditions at room temperature. The ensuing aryl diazonium salts supported on nano-SPIA were sufficiently stable to be kept at room temperature in the dry state. This method is a novel, efficient, eco-friendly route for solvent-free synthesis of aryl iodides.

Magnetic CoFe2O4 nanoparticles were synthesized via a simple chemical reaction using precipitation method. The obtained materials consist of ferrite particles with average diameter of 25 nm. The effect of different surfactants such as cationic, anionic and neutral on the morphology of the products was investigated. Scanning electron microscopy was used to study the structure and particle size of CoFe2O4 nanoparticles.Magnetic properties of the product were also examined by vibrating sample magnetometer at room temperature. By using ammonia and sodium hydroxide cobalt ferrite nanoparticles exhibit different super-paramagnetic and ferrimagnetic behaviors respectively.

In this research, structural and electronic properties of ZnCdn-1Ten clusters (n=1-10) have been studied by formalism of density functional theory and using the projector augmented wave within local density approximation. The structural properties (such as bond length/angle and coordination number), electronic and optical properties (such as binding energy, Kohn-Sham spectrum and partial charge density, absorption spectrum) of ZnCdTe clusters were investigated and compared to these of CdTe clusters. A transition from Two-dimensional (2D) to Three-dimensional (3D) structures is observed from n=5®n=6. Results obtained for the most stable geometrics of the ZnCdTe clusters show that a Zn atom increases binding energy and consequently stability of CdTe clusters. It also decreases (increases) bond lengths (angles) for it’s nearest neighbor atoms. An analysis of partial charge density and eigenvalue spectrum for ZnCdn-1Ten clusters reveals that there are Te- s and Cd- d hybridizations for low energy levels.

A simple and efficient method for the synthesis of quinolines and polycyclic quinolines using Li+ modified nanoporous Na+- montmorillonite is described. This new nanocatalyst proceeds via Friedlander annulation under solvent-free conditions. It describes our observations about a trend of catalytic activity of Lithium cation in nanoporous Na+-montmorillonite. In this study, several types of 1, 3-diketones such as 1, 3-cyclohexanedione, 1, 3-cyclopentandione, 5, 5-dimethylcyclohexandione (dimedone), acetylacetone and ethyl or methyl acetoacetate and 2-aminoarylketones were rapidly converted to the corresponding substitutedquinoline derivatives in good to excellent yields. The simple experimental procedure, solvent-free reaction conditions, good yields, and utilization of an inexpensive and reusable catalyst are the advantages of the proposed method. To the best of our knowledge, this is the first report on the synthesis of quinoline derivatives using Li+modified in nanoporous Na+- MMT as a novel nanocatalyst under solvent-free conditions. The catalysts can be recovered for the subsequent reactions and reused without any loss of efficiency.

In this research, the surface stress effect on the nonlocal vibration of piezoelectric square plate reinforced by single walled carbon nanotubes (SWCNTs) based on classical plate theory (CPT) and first order shear deformation theory (FSDT) is presented. The elastic properties of piezoelectric nanocomposite plate are estimated by Eshelby-Mori-Tanaka and the extended mixture rule approaches.The motion equations of nanocomposite plate are obtained using Hamiton's principle. The Navier's type solution is used to solve these equations. There is the best agreement between the obtained analytical results and other literature results. Then the effects of various parameters such as elastic foundation, surface stress, agglomeration, applied voltage and magnetic field on the nonlocal natural frequency of piezoelectric square nanocomposite plate are investigated. It is concluded that the non-dimensional frequency ratio decreases with increasing the SWCNT volume fraction in the inclusion (agglomeration effect), nonlocal parameter and residual surface stress constant for both CPT and FSDT. Also it is seen that a change in the applied voltage, magnetic field intensity, elastic foundation parameters and surface density leads to increase the non-dimensional frequency ratio.

Spherical granules of the superionic conductor b/ b LiZr2 (PO4) 3 in the range of sub 100 nm sizewere synthesizedvia freeze drying methodand fully reviewed in all aspects. Samples were characterized by the X-ray diffractometry (XRD), the Thermal analysis (TG, DSC), theFourier Transform Infra-Red Spectroscopy (FTIR) and the Scanning Electron Microscopy (SEM).Their structuredepends largely on the method of synthesis, thermaltreatment, and conditions of storing samples. Degree of Crystallinity and phase purity in different annealing time were tested. The synthesize temperature does not exceed 873 K in any step of the synthesis.The low temperature phases (b with the Pbna space group and b’ with the P21/n space group) were preparedat optimum condition. By the Differential Scanning Calorimetry it was shown the phase transition from b  « b’ occurred at about 567-597 K. The temperature of annealing the phosphate and calcination time is not very effective to phase transition temperature.

Polymer nanocomposites containing metals have been used in a wide range of applications due to their versatility, and tunable characteristics including physical, chemical, biological and mechanical properties. In this research work polystyrene-silver nanocomposite has been produced using polymerization of a w/o microemulsion system. Styrene monomer was used as the oil or continues phase of the microemulsion system and polymerized following formation of Ag nanoparticles in the fluid medium. The UV-vis absorption and dynamic light scattering methods have been used to trace the growth process and size distribution of the Ag nanoparticles in the microemulsion system. Scanning electron microscopy (SEM) was used to determine the morphology and particle size of the Ag particles in the synthesized nanocomposites.

Magnesium hydroxide nanostructures as an effective flame retardant were synthesized by a facile and rapid microwave reaction. The effect of different surfactants such as cationic, anionic and polymeric on the morphology of magnesium hydroxide nanostructures was investigated. Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transforminfrared (FT-IR) spectroscopy. The influence of Mg (OH)2 nanostructures on the thermal stability and flame retardancy of the poly vinyl alcohol (PVA) matrix was studied using thermogravimetric analysis (TGA) and UL-94 respectively. Thermal decomposition of the nanocomposites shift towards higher temperature in the presence of Mg (OH)2 nanostructures. The enhancement of thermal stability and flame retardancy of nanocomposites is due to the endothermic decomposition of Mg (OH)2 and release of water which dilutes combustible gases.