International Journal of Nanoscience

Physical vapor deposition techniques such vacuum arc plasma deposition — which are very commonly used in thin film technology — appear to hold much promise for the synthesis of nanocrystalline thin films as well as nanoparticles. Monodisperse and spherical titanium oxide (TiO₂) and nitride nanoparticles were produced at room temperature as a cluster beam in the gas phase using a cluster-deposition source. Using the basic principles of the gas condensation method, this study has developed vacuum arc nanoparticle synthesis system. We demonstrate that major process deposition parameter is the pressure in the plasma chamber. This is the major advantage of these techniques over thermal evaporation. Our method affords TiN powders with high specific surface areas exceeding 200m²g${}^{-1}$. TEM micrograph of TiO₂ nanoparticles prepared at an oxygen pressure of 60Pa show an average particle size of 6nm. TiO₂ nanoparticles prepared at an oxygen pressure of 70Pa were observed to not have a reduced average particle size.

Electrolysis is a method used for producing copper (Cu) nanoparticles at faster rate and at low cost in ambient conditions. The property of Cu nanoparticles prepared by electrolysis depends on their process parameters. The influence of selected process parameters such as copper sulfate (CuSo₄) concentration, electrode gap and electrode potential difference on particle size was investigated. To optimize these parameters response surface methodology (RSM) was used. Cu nanoparticles prepared by electrolysis were characterized by using X-ray diffraction (XRD) and scanning electron microscope (SEM). After reviewing the results of analysis of variance (ANOVA), mathematical equation was created and optimized parameters for producing Cu nanoparticles were determined. The results confirm that the average size of Cu particle at the optimum condition was found to be 17nm and they are hexagonal in shape.

The nanocrystalline TiO₂ powder was synthesized by sol–gel method. The XRD analysis reveals that TiO₂ powder was highly crystalline (anatase phase) and nanostructured with tetragonal system. The average crystallite size after calcined at 673K is found to be 7.7nm. The surface morphological studies using scanning electron microscopy (SEM) exhibit that the formation of nanosized TiO₂ particles with less densification nature. Atomic force microscopy (AFM) topography exhibits the uniform distribution of spherical-shaped particles. The energy dispersive X-ray spectroscopy (EDX) confirms the presence of Titanium and Oxygen in synthesized TiO₂ nanopowder. The value of optical bandgap of TiO₂ nanopowder calculated from UV-Visible spectrum is 3.45eV. The presence of TiO₂ particles is confirmed from the dominant fourier transform infrared (FTIR) peaks at 621cm${}^{-1}$ and 412cm${}^{-1}$.

In this paper, we have studied the effect of a number of wells and quantum dot thickness on binding energy of a single donor impurity confined within a CdS-SiO₂ constant total effective radius multi-shells quantum dot (CTER-MSQD) system. We have shown that impurity binding energy versus number of wells in a quantum dot with fixed outer radius oscillates when amplitude increases. By using well number variation, adding impurity and changing quantum dot radius as three tuning tools, localization of wave-functions in each part of the quantum dot along the radius has been now made possible. Finally, adding the impurity leads to more probability of finding the electrons in the wells near the center of the quantum dot.

Nylon-6 is an engineering plastic with excellent properties and processability, which are essential in several industrial applications. The addition of filler such as diamond (DN) and diamond coated carbon nanotubes (CNTs) to form molded composites may increase the range of Nylon-6 applications due to the resulting increase in strength. The effects of electron-beam irradiation on these thermoplastic nanocomposites are either increase in the cross-linking or causes chain scission. In this study, DN-coated CNTs were synthesized using the sonochemical technique in the presence of cationic surfactant cetyltrimethyl ammonium bromide (CTAB). The DN-coated CNTs nanoparticles and diamond nanoparticles were then introduced into Nylon-6 polymer through a melt extrusion process to form nanocomposite fibers. They were further tested for their mechanical (Tensile) and thermal properties (thermogravimetric analysis (TGA), differential scanning calorimetry (DSC)). These composites were further exposed to the electron-beam (160kGy, 132kGy and 99kGy) irradiation using a 1.5MeV electron-beam accelerator, at room temperature, in the presence of air and tested for their thermal and mechanical properties. The best ultimate tensile strength was found to be 690MPa and 864MPa irradiated at 132 for DN/CNTs/Nylon-6 and Diamond/Nylon-6 nanocomposite fiber as compared to 346MPa and 321MPa for DN/CNTs/Nylon-6 and Diamond/Nylon-6 nanocomposite fiber without irradiation. The neat Nylon-6 tensile strength was 240MPa. These results are consistent with the activation energy calculated from TGA graphs. DSC analysis result shows that the slight increase in glass transition temperature ($T_g$) and decrease in melting temperature ($T_m$) which was expected from high electron-beam radiation dose.

Electrospun nanofibrous materials are widely used in medical applications such as tissue engineering scaffolds, wound dressing material and drug delivery carriers. For tissue engineering scaffolds, the structure of the nanofiber is similar to extracellular matrix (ECM) which promotes the cell growth and proliferation. In the present study, the aligned nanofiber mats of polyvinyl pyrrolidone (PVP) blended poly $\epsilon$-caprolactone (PCL) was successfully generated using electrospinning technique. The morphology of PVP/PCL nanofiber mats were characterized by scanning electron microspore (SEM). The chemical and crystalline structure of PVP/PCL nanofiber mats were analyzed using Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffactometer (PXRD). The water contact angle of mats was investigated. Cell culture studies using normal human fibroblasts (NHF) were performed to assess cell morphology, cell alignment and cell proliferation. The results indicated that the fiber were in nanometer range. The PVP/PCL was well dispersed in nanofiber mats and was in amorphous form. The water contact angle of PVP/PCL nanofiber mats was lower than PCL nanofiber mats. The PVP/PCL nanofiber mats exhibited good biocompatibility with NHF cells. In summary, the PVP/PCL nanofiber mats had potential to be used in tissue engineering and regenerative medicine.

In the present work, Zinc Oxide nanoparticles (ZnO Nps) have been prepared by a simple and low temperature solution combustion method using Zinc nitrate as a precursor and solid water melon juice as a novel fuel for the first time. The structure and morphology of the synthesized ZnO NPs have been analyzed using various analytical techniques such as Powder X-ray diffraction, FTIR spectroscopy, Raman spectroscopy, UV-Visible spectroscopy, photoluminescence spectroscopy, scanning electron microscope and transmission electron microscope. ZnO NPs show good photo catalytic activity for the degradation of methylene blue (MB) dye. It also shows significant antibacterial activities against three bacterial strains.

We investigated the structural, electrical and optical properties of zinc oxide thin films as the n-type semiconductor. In the present paper, the effect of substrate temperature on the synthesis of ZnO thin films was carried out from 250${}^{\circ }$C to 500${}^{\circ }$C. ZnO thin films were deposited on glass substrates via ultrasonic spray technique with 0.2mol/L of zinc acetate dehydrate. The crystal quality of the thin films was analyzed by X-ray diffraction which results in modified substrate temperature. The optical transmittance and electrical conductivity measurements were carried out by Ultraviolet-visible spectrophotometer and four-point methods, respectively. Polycrystalline films with a hexagonal wurtzite structure with (100) and (002) preferential orientation corresponding to ZnO films were observed at high temperature. The optimal values of the average crystallite size of the ZnO films under consideration are observed beginning with 350${}^{\circ }$C of substrate temperature. All films exhibit an average optical transparency of about 85% in the visible region. The shift of optical transmittance toward higher wavelength can be shown by the increase of bandgap energy from 3.245eV to 3.281eV with increasing substrate temperature of 250–500${}^{\circ }$C. The observed Urbach energy of ZnO thin films decreases from 0.11311eV to 0.04974eV. At a high temperature, the electrical conductivity of ZnO films was increased from $3.87\times 10^{-3}$ to 41.58 ($\mathrm{\Omega }$.cm)${}^{-1}$ with the increasing substrate temperature from 350${}^{\circ }$C to 500${}^{\circ }$C.

Aquatic pteridophyte (Azolla sp.) was taken to assess its potential to synthesize the metal (Au) nanoparticles. The synthesized particles were characterized using X-ray, UV-visible, scanning and transmission electron microscopy analyses. Nanoparticles almost spherical in shape having the sizes of 5–17nm are found. UV-visible study revealed the surface plasmon resonance at 538nm. Responsible phytochemicals for the transformation were principally phenolics, tannins, anthraquinone glycosides and sugars present abundantly in the plant thereby bestowing it adaptive prodigality. Also, the use of Azolla sp. for the synthesis of gold nanoparticles offers the benefit of eco-friendliness.

We study the quantum capacitance $C_q$ in the objects with completely discrete structure of electron states as a result of both dimensional quantization and applied magnetic field. The capacitance is analyzed in such objects as nanoplates of metal, semiconductor and semimetal. Factors which define the form of the dependence of $C_q$ on the position of the Fermi level or potential bias, and magnetic field, are analyzed.

Intercalation of salicylate (Sal) into layered zinc hydroxide nitrate (ZHN) nanohybrid materials was successfully synthesized by the coprecipitation method. The effect of pH, crystallization method, temperature and time of hydrothermal treatment on preparation was investigated in detail and compared. The products were confirmed by X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry and differential thermal analysis (TG-DTA), and scanning electron microscope (SEM). The results revealed that ZHN–Sal with pure phase and good crystallinity was obtained at pH = 6.0–6.5, 60${}^{\circ }$C and 3h of temperature and time of hydrothermal treatment. The TG-DTA data indicated that the intercalated Sal had a high stability compared to the isolated. And the phases and compositions of the sample calcined at increasing temperatures were also identified by XRPD and FTIR techniques. Furthermore, ZHN–Sal exhibited an improved UV-blocking ability, showing it can be used as a potential alternative matrix for the UV blocker.