Journal of Nano Structures
Volume:9 Issue: 4, Autumn 2019

Cadmium tungstate (CdWO4) nanorods and CdWO4-reduced graphene oxide (RGO) nanocomposites have been prepared by the hydrothermal method at 140, 160 and 180 oC reaction temperatures. The synthesized samples were characterized by X-ray powder diffraction, scanning electron microscopy (SEM), Fourier transform infrared, photoluminescence spectroscopy and Raman spectroscopy. SEM image showed the pure sample consist of nanorods with 50-100 nm diameter and ~1 µm length. The images of the nanocomposite samples clearly showed existence of CdWO4 nanorods and graphene sheets together. The photocatalytic activities of the as-prepared samples were investigated by degradation of methylene blue under the visible light irradiation. An enhancement in photocatalytic activity was observed with CdWO4-RGO nanocomposites in compare with the pure CdWO4. The effect of reaction temperature on the photocatalytic activity of the prepared nanocomposites was also investigated. The results showed that the CdWO4-RGO sample which prepared at 160 oC has more catalytic activity than the other samples.

At first step polymer optical fibers (POFs) are used in short distance for optical data transmissions. At second step SiO2 nanoparticles were prepared by sonochemical-assisted method. Silica nanoparticles were added to polymer matrix to prepare polymer based nanocomposites. Most of the POF applications are in the medical and electrical devices. There are several methods for fabrication of POFs, description of which are given in this paper. We have designed a special co-extruder system for fabricating POF. The POFs fabricated by this device are very homogeny and their core and cladding have good viscidity. Key Words: Polymer optical fiber, Preform, Extrusion, Coating, Cladding, Silica ABSTRACT At first step polymer optical fibers (POFs) are used in short distance for optical data transmissions. At second step SiO2 nanoparticles were prepared by sonochemical-assisted method. Silica nanoparticles were added to polymer matrix to prepare polymer based nanocomposites. Most of the POF applications are in the medical and electrical devices. There are several methods for fabrication of POFs, description of which are given in this paper. We have designed a special co-extruder system for fabricating POF. The POFs fabricated by this device are very homogeny and their core and cladding have good viscidity.

Gadolinium oxysulfide phosphor doped with trivalent terbium have been synthesized using urea homogenous precipitation and followed by sulfurization at 800 °C under argon atmosphere. Structural and morphological of synthesized phosphor powder were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FT-IR). Hexagonal structure of Gd2O2S:Tb3+ phosphor was confirmed by XRD. Compositional analysis were carried out by energy dispersive x-ray (EDX) and particle induced x-ray emission (PIXE). Photoluminescence emission spectra was measured by fluorescent spectrometer. A sedimentation technique is used to deposit the phosphor powder directly on the glass substrate using poly vinyl alcohol as a paste. A number of phosphor layers have been synthesized with the layer thickness ranging from 150 to 268 µm. Measurement results of x-ray conversion efficiency for layers were investigated using 300 kVp X-ray tube in which the maximum light output and contrast were observed for layer with a thickness of 193 µm. Oxysulfide phosphor layer was analyzed by ion beam induced luminescence (IBIL). Emitting of green light from phosphor layer confirm its luminescence property.

Sphere-like cadmium molybdate (CdMoO4) nanostructures have been synthesized by a large scale and simple sonochemical method by using Cd(Sal)2 (Sal=salicylidene) and Na2MoO4.2H2O for the first time. The effects of sonochemical irradiation time, sonochemical power, temperature, solvent, surfactant and cadmium source were considered to obtain a controlled shape. The as-prepared nanostructured cadmium molybdate was analyzed by UV–Vis diffuse reflectance spectroscopy (DRS), energy dispersive X-ray microanalysis (EDX), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). It was established that morphology, particle size and phase composition of the final products could be greatly affected by these parameters. The photocatalytic activity of the synthesized products has been compared for the photo- degradation activity of methylene blue (MB). The distinguished degradation activity of cadmium molybdate photocatalyst can be ascribed to the powerful UV light absorption, excellent charge separation efficiency, nice particle size distribution and proper band gap of the nanostructures.

In this work, the investigation of wave absorption, phase formation, crystal structure and magnetic properties of SrFe12O19 hexa-ferrites nanoparticles that synthesized by co-precipitation using a microwave heating system and polyaniline-SrFe12O19 was carried out by using a combination of vector network analyser (VNA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. Alternating gradient force magnetometer proofs the magnetic property of the hexa-ferrite nanostructures. We studied Sr Hexa-ferrite nanoparticles and nanocomposite by changing in many parameters like power of microwave system and calcination temperature.In this work, the investigation of wave absorption, phase formation, crystal structure and magnetic properties of SrFe12O19 hexa-ferrites nanoparticles that synthesized by co-precipitation using a microwave heating system and polyaniline-SrFe12O19 was carried out by using a combination of vector network analyser (VNA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. Alternating gradient force magnetometer proofs the magnetic property of the hexa-ferrite nanostructures. We studied Sr Hexa-ferrite nanoparticles and nanocomposite by changing in many parameters like power of microwave system and calcination temperature.

We present a general study on a high performance supercapacitor based on intercalated reduced graphene oxide with carbon black nanoparticles. Graphene oxide sheets were synthesized by oxidation and exfoliation of natural graphite and were reduced using hydroiodic acid in the presence of carbon black nanoparticles. Graphene paper was fabricated by one-step procedure via simultaneous reducing and drying the aqueous solution of mixed carbon black nanoparticles and graphene oxide on a conductive substrate. Transmission electron microscopy confirmed the intercalation of carbon black nanoparticles into reduced graphene oxide sheets, preventing them from restacking during the fabrication of paper. Results confirmed that the electrochemical performance of the reduced graphene oxide paper as a supercapacitor electrode was improved by intercalation of carbon black nanoparticles into reduced graphene oxide sheets and also the assembled supercapacitor becomes more efficient with graphene oxide separator. Cyclic voltammetry of the prepared electrodes in 30 wt% KOH solution at 10 mV/s scan rate showed that adding only 5 wt% of carbon black to graphene oxide increases specific capacitance from 118 F/g to 129 F/g. In addition, the maximum specific capacitance (139 F/g) was obtained by adding 15 wt% of carbon black and that increased to 142 F/g by the use of graphene oxide paper as a separator. Furthermore, electrochemical impedance spectroscopy by Nyquist plot showed that charge transfer resistance in electrodes decreases from 18 in the reduced graphene oxide to 6 in the reduced graphene oxide paper with intercalated carbon black nanoparticles and ions diffusion occurs easier than previous.

Lead zirconate titanate (PZT) nanopowders with spherical-shaped morphology, perovskite structure and an average size of 20 nm were successfully synthesized. The prepared PZT nanopowders were characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive X-ray (EDS) and Transmission electron microscopy (TEM) technique. Single-phase perovskite PZT nanopowders were obtained after heat treatment at a temperature of 700 °C. The effect of calcination temperature on crystal structure of PZT nanopowders has been discussed. Dielectric relaxation of the ferroelectric ceramics could originate from the alternations of the elastic and electric behavior and the movement of the domain walls at high-frequency regions. To determine a piezoelectric property of ceramics, resonant vibration spectrum of samples was measured at room temperature. A relative density of 7.53 g/cm3 was achieved at a sintering temperature of 1150 °C, which is close to the theoretical density (~95%). At higher temperature sint, the density of ceramic samples strongly decreases which can be attributed to the evaporation of excess PbO. The optimum values of piezoelectric constant, electromechanical quality factor and a mechanical quality factor are obtained at Sintering temperature 1150 °C: d33=64 pC/N, Ƙp=0.41 and Qm=34.3.

Current work proposes an inimitable composite, with great electrical conductivity and quite enhanced surface area, (including conducting polymers (poly (cathechol)), Cu2O–carbon dots and green synthesized gold nanoparticles) for detecting acute carcinoembryonic antigen. At current work, the electropolymerization was offered instead of enzyme-catalyzed polymerization of poly (catechol). Four cost-effective electrochemical techniques (Differential Pulse Voltammetry, Electrochemical Impedance Spectroscopy, Cyclic Voltammetry and Crono amperometry) were engaged to investigate aptasensors construction, immobilization, hybridization, sensitivity, selectivity, repeatability, long-term stability and real PCR sample detections. According to the data, the values of Ipeak is linearly related to the logarithm of the concentrations of carcinoembryonic antigen in the range from 1.0 pg mL-1 to 0.001 g mL-1, with a detection limit of 0.19 pg mL-1 for the target antigen (carcinoembryonic antigen).

An efficient procedure and green route has been developed by using eco-friendly green synthesized palladium nanoparticles (Pd-NPs) as reusable heterogeneous nanocatalyst (Pd@nanocat) for the synthesis of diaryl ethers from the cross coupling reaction of the aryl halides with the phenol in the presence of dimethylsulfoxide (DMSO) as a solvent at 110 oC under natural ligand condition capped Pd-NPs. The generated Pd-NPs were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. Structural characterization of diaryl ether was done by nuclear magnetic resonance spectroscopy (NMR). The nanoparticles exhibited stability, reusability with excellent catalytic activity and the results of this study demonstrate the possible application of biosynthesized Pd-NPs as heterogeneous nanocatalyst in environmental remediation. Application of the cheaper base, shorter reaction time, cost-effective, high yield and environmentally friendly make our conditions potentially useful and more suitable to other reported works, which could be amenable to scale-up.

In this research, Zn2SiO4 as a support and MnFe2O4 as a main photo-catalyst were individually syn-thesized and MnFe2O4 was fixed on Zn2SiO4 with solid state dispersion method. MnFe2O4 nano pho-to-catalyst was synthesized by co-precipitation method and reflux condition for 12 hours at 85°C in the presence of urea. For identification of catalysts Fourier-transform infrared (FTIR) spectroscopy, Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDXS), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray fluorescence (XRF) and Brunauer-Emmett-Teller (BET) techniques were used. The size of MnFe2O4 was determined about 15 nm after the fixation on the Zn2SiO4. The photo-catalytic efficiency of MnFe2O4/Zn2SiO4 was checked for degradation of aniline aqueous solu-tion utilizing the irradiation of a 1 kW Xe lamp fitted with the AM1.5 filter (to simulate the solar light spectrum) in the presence of H2O2. Degradation process was modeled and optimized successfully ap-plying response surface methodology (RSM) according to Box-Behnken designs. Experiment results were showed that initial concentration of aniline=5.5 ppm, H2O2 initial concentration=5.3 mM, pH=11 and nano photo-catalyst amount =0.4 g/L are optimal conditions and the degradation effi-ciency in this condition achieved is 96%. In the optimum conditions, arrangement of (MnFe2O4/Zn2SiO4)> (MnFe2O4)> (Zn2SiO4) was obtained for efficiency of photo-catalytic degrada-tion of aniline in aqueous solution. Decomposition kinetic equation determined pseudo first order and k=0.0407.

In the present study, new multi-components spinel ferrite Zinc doped metallic ferrites are investigated. The synthesized compounds consisting of Zinc copper ferrite nanostructures were developed using the Co-precipitation technique. Powder X-ray diffraction pattern (XRD) confirms the formation of the spinel phase for all the samples. The lattice constant was studied through powder X-ray diffraction data analysis. The lattice constant of all Zinc copper ferrite concentration was found to be less than that of bulk values. The chemical composition, surface morphology and crystallinity of the samples have been examined by scanning electron microscopy (SEM) and High-Resolution Transmission Electron Microscope (HRTEM). Besides, selected area electron diffraction (SAED) confirms the evolution of phases and Energy Dispersive X-ray (EDX) respectively. The effect of Zinc copper ferrite nanoparticles, the magnetic properties were investigated by using Vibration Sample Magnetometer (VSM). The obtained hysteresis (M-H) curves of all the samples were analysed under the applied magnetic field of range ± 10 K Oe at room temperature. The magnetic properties such as saturation magnetisation (Ms), remnant magnetization (Mr) and coercivity (Hc) values are calculated. The data obtained from magnetic studies, the variation among the magnetic properties have been investigated for annealed 600 °C sample. The prepared Zinc copper ferrite nanoparticles should be extended to various potential applications, such as photodegradation of methylene blue (MB) dye under visible-light irradiation and results showed that 65% of the dye was degraded. Catalysis, separation, and purification processes.

The present paper focuses on the investigation of self-cleaning properties based on studding of water repellency and blood repellency for TiN- and CrN single-layer and TiN/CrN nanoscale multi-layer coatings deposited via Cathodic Arc Evaporation (CAE) method on medical grade 420C stainless steel substrate. X-ray diffraction (XRD) method and Field Emission Scanning Electron Microscope (FESEM) was used to characterize microstructure. Surface roughness parameters were measured by using Taylor-Habsson method. Blood contact angle and water contact angle measurements test were applied to characterize the self-cleaning properties of the specimens. The analysis of sample data shows that coated specimens have more water contact angle values in comparison to bare steel. Among the coated samples, CrN single-layer has the highest water contact angle (80°) due to its lower surface roughness (Ra=0.189µm) among the other samples. Moreover, the findings of the paper prove that samples had inverse behavior against blood and water in the contact angle measurement test. Bare steel has higher blood contact angle (76.1°) and more blood repellency than the coated specimens. It seems that the different behavior of samples against water and blood in contact angle tests is due to the nature of two fluids. TiN/CrN multi-layer coating results had minor differences in water and blood contact angle tests (67.3° and 62.2° respectively).

A novel series of the Co/Zn-MSN catalysts with Si/Zn molar ratio of 10 and 1, 3, 5 and 7 wt% Cobalt (denoted by CZ-X-MSN) were synthesized using post-synthesis methods. The samples were characterized by XRD, SEM, FTIR, TEM and nitrogen sorption methods. With a constant Si/Zn ratio, the increase of cobalt species from 1 to 7 wt% led to decrease the catalysts surface area from 408 m2g-1 for CZ-1-MSN to 322 m2g-1 for CZ-7-MSN. The catalyst activities were investigated for Schiff base synthesis by the reaction of cyclohexanone with 2,4-dinitrophenylhydrazine under UV irradiation. The activity of the catalysts in the Schiff base synthesis followed the order of Zn-MSN-10 < CZ-1-MSN < CZ-7-MSN < CZ-3-MSN < CZ-5-MSN. The CZ-5-MSN sample exhibited the highest performance with the conversion and selectivity of cyclohexanone to the Schiff base product were 98 and 97%, respectively, under UV light at 298 K for 10 min. The superior catalytic performance of CZ-5-MSN includes high yield, low reaction temperature, short reaction time and friendly environment. This probably was related to stronger metal-support interaction and metals dispersion. This study provides the new perspective on the synthesis of CZ-X-MSN towards an excellent performance of Schiff base structure under UV irradiation.

Frequent use of synthetic larvicides has led to the development of resistance in many species of mosquitoes as well as risk of environmental pollution. Recently, encapsulating essential oils (EOs) in surfactants or polymers is being employed as an approach to control the volatility of EOs as green larvicides. In this research, components of tarragon (Artemisia dracunculus) essential oil were identified by GC-MS analysis. Forty-eight components were identified, with 5 major components including estragole (67.623%), cis-Ocimene (8.691%), beta-Ocimene Y (7.577%), Limonene (4.338%) and 3-Methoxy cinnam aldehyde (1.49%). Tarragon EO was encapsulated in chitosan nanocapsules using ionic gelation method and confirmed by FT-IR analysis. Encapsulation efficiency and size of the chitosan nanocapsules were determined 34.91 ± 2% and 203 ± 16 nm, respectively. For the first time, a long-lasting green larvicide was reported which remained active for 10 days, against Anopheles stephensi. Furthermore, cytotoxicity of the nanoformulation was found to be similar to that of temephos on human skin normal cells (HFFF2). This nanoformulation can be a good alternative for synthetic larvicides due to its long-lasting activity, proper effectiveness and also its green constituents.

In this research, inorganic material type and content influence on coating of commercially available polypropylene (PP) separator were studied for improving its performance and safety as lithium ion battery separator. Heat-resistant nanopowders of Al2O3, SiO2 and ZrO2 were coated using polyvinylidene fluoride (PVDF) binder. Coating effects on the separators morphology, wettability, high temperatures dimensional stability and electrochemical properties were investigated via their scanning electron microscopy images, electrolyte contact angles, electrolyte uptakes, thermal shrinkages analysis and ion conductivities. Furthermore, their performances were studied as the lithium ion batteries separator. All the coated separators have lower thermal shrinkages compared to the commercial neat PP separator. In addition, almost all of the coated separators have shown higher porosities and electrolyte uptakes than those of the commercial neat PP separators. The coated separator with Al2O3 / binder ratio of 8 (MOA8) revealed highest improvement in electrolyte contact angle of 0 °, electrolyte uptake of 218 % (2.04 times increment), ion conductivity of 1.685 mS/cm (1.89 times increment), 52 % porosity compared with the neat PP separator due to proper coating surface morphology, interstitial cavities and a higher Al2O3 dielectric constant than SiO2. In terms of assembled battery discharge capacity reduction after 100 cycles, MOA8 separator showed better cyclic performance as 8.89 % compared with that of the neat PP separator as 16.6 %.

The structure and morphology of nonmaterial formed by colloidal synthesis represent a subject of interest as it is a factor deciding the physicochemical properties and biological applications of nanostructures. Among various nanoparticles, gold can develop fractal assembled patterns. Herein, we report a nano-aggregate of a thiol-on-gold self-assembled structure and the influence of β-cyclodextrin on the self-assembly. The host: guest association of the 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol is studied using UV-visible, fluorescence spectroscopy and molecular modelling analysis. In free form unbound to gold nanoparticles, the thiol compound forms a cyclodextrin complex with a 1: 1 stoichiometry. The thiol assembled on gold nanoparticles, aggregating to constitute irregular patterns. β-cyclodextrin encapsulates the thiol-on-gold nanoparticles and their morphology changes. The influence of β-cyclodextrin on the aggregation of the thiol guest molecule and the morphology of the thiol-on-gold nanostructure is discussed. The non-covalent complex made up by the thiol molecule with cyclodextrin plays a vital role in tuning the structure of the nanostructure when assembled on gold nanoparticles.The study will open up a significant method in the approach towards site specific drug delivery via a physical encapsulation.

In this study CuO nano sheets were prepared using the cellulose extracted from green synthesis (cotton) as a novel me project. Structural properties were examined using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Ultra Violet (UV-Vis). The optimum copper oxide peak was at 2 theta 〖35.44〗^°corresponding to (1 ̅11) while for the cellulose was 〖22.8〗^°corresponds to (002). FESEM images of CuO nano sheets were relatively homogenous with diameters less than 30 nm. The UV-Vis for CuO-cellulose nano rods was observed at 350-360 nm, which is higher than of pure CuO nano sheet. The energy band gaps were 3.20 eV and 3.30 eV of CuO and CuO-CNR respectively. Finally antimicrobial activities of samples have been investigated against the Gram positive (pneumonia) and gram-negative (pseudomonas). The maximum antibacterial activities against the Gram positive (pneumonia) of CuO nano sheet and of CuO- cellulose nano rods are 16 mm and 19 mm respectively. The maximum antibacterial activities against the Gram negative (pseudomonas) of CuO nano sheet and of CuO- cellulose nano rods are 30 mm and 33 mm.

Synthesis and characterization of Cd-TiO2/PEG/FA nanocomposite as a biomaterial is the main aim of this research. Cd-doped TiO2 nanoparticles (NPs) were synthesized by solvothermal assisted sol-gel method. Then, polyethylene glycol (PEG) was added to the as-synthesized NPs in order to modify their surface and to prevent agglomeration. In the next step, folic acid (FA) was conjugated to Cd-TiO2/PEG nanocomposite. Optimization of FA concentration and influence of ultraviolet (UV) radiation, visible light, or ultrasonic irradiation on antibacterial activity of the synthesized nanocomposite were assessed. Results showed that the influence of FA on the antibacterial performance of the as-synthesized compounds is positive and dose-dependent. FA was used as bait for bacteria and led them to accumulate around the Cd-TiO2 NPs. The bactericidal response under UV or visible light irradiation was maximized at 0.6 weight ratio of FA to Cd-TiO2, whereas, this parameter under ultrasonic irradiation was improved and then became approximately constant.

Abstract. Cubic crystalline oxides such as Y2O3 and MgO is used to stabalized zirconia phases at high temperature. In this paper the Y2O3 powder was added to stabilized zirconia and preparing a mixture of MgAl2O4 Spinel by mixing 1mol of nano-MgO with 1 mol of nano-Al2O3 powders. The spinel was added to the Y2O3-ZrO2 by various weight percentage (5, 10, 15, 20 and 25 wt%), and after that the specimens was prepared by axial pressing and sintered at 1550 oC for 4 hours as soaking time. The grain size was tested by using Atomic Force Microscopy (AFM) and calculated for surface of specimens and it was found to be decreasing (> 0.6 µm) to (~ 108 nm). The thermal properties were clearly influenced by the structural characteristics of the MAS. The thermal conductivity and thermal diffusion was decreased slightly from 5.7 to 5.5 W/m.K and from 2.5 to 1.5 mm2/s, respectively. The thermal capacity was increased from 483 to 615 J/kg.K, and thermal expansion coefficient was increased from 10 to 7.510-6 oC-1 due to the compatibility of thermal expansion coefficients of (Y-PSZ)-MAS oxides. Thermal properties values are compatible with thermal insulation requirements in energy storage applications.

In this investigation, curcumin niosomal nanoparticles were prepared via a simple, efficient and eco-friendly route, thin film hydration (TFH), in the presence of different mixture of the surfactants (tween 60 and span 60). Cholesterol ratio to surfactant, as effective factor, was altered to obtain the optimal nanoparticles. The size, zeta potential, size distribution, entrapment efficiency of the prepared nanoparticles were examined and compared. The optimum nanoparticles were chosen to examine the release from the dialysis membrane. Ratio of cholesterol to surfactant was found to have key and notable influence on the size, zeta potential, size distribution, entrapment efficiency of the prepared nanoparticles. The nanoparticles prepared with Formulations 3 and 5 as optimum nanoparticles were chosen to examine the release from the dialysis membrane. The results denoted that by increasing the ratio of cholesterol to surfactant, the rate of curcumin release was enhanced from the membrane. High quantities of cholesterol in the formulation 3, in addition to explosive release, can lead to slow release.