Preparation Of Nano Research Articles

DNA gel nanoparticles: preparation and controlling the size

A simple and novel method was used for the preparation of nano-/micro-sized DNA gel particles by nebulisation of a solution of DNA (single- or double-stranded) into an oppositely charged surfactant (cetyltrimethylammonium bromide) or protein (lysozyme, protamine sulfate) solution. The size and size distribution of the particle populations were investigated by means of fluorescence microscopy (FM), photon correlation spectroscopy (PCS) and scanning electron microscopy (SEM). Particles measuring from 0.1 to 10 µm were obtained. FM studies suggest that the formation of the particles was carried out with conservation of the secondary structure of the nucleic acid molecules. SEM on freeze-dried and Au-shadowed samples showed a distribution of virtually spherical particles. It was found that, in addition to the size of the initial DNA droplets, the cationic agent is a controlling parameter of the particle size.

ChemInform Abstract: Preparation and Properties of Magnetic Nano‐ and Microsized Particles for Biological and Environmental Separations

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Preparation of Nano- MgO and Investigation of its Infrared Absorption Properties

A precipitation-pyrolysis process was developed for the synthesis of MgO nano-particles with diameter of 20~100 nm by using organic reagent, glycol, n-butanol and N,N-Dimethylacetamide, as shape and size controller. XRD and TEM were used to study on composition, morphology and size of the as prepared MgO nanoparticles. The results indicate that organic crystal controller is one of the key factors affecting the sizes and shapes of the nano MgO particles. When using glycol as a crystal controller, the dispersion of nano MgO particles is better and olive-shaped particles with sizes of 20~40 nm are prepared. When nano MgO particles are synthesized by MgCl2 and Mg(NO3)2, their particle sizes are smaller and their particles with olive shape. During chemical reaction process, Mg(OH)2 particles are already formed to be nano scale. Calcination process at the temperature of 650°C can change the crystal shape slightly. FTIR results show that nano MgO particles have abnormal infrared absorption behaviors compared with that of micron scale.

Preparation of Nano Carbonate‐Substituted Hydroxyapatite from an Amorphous Precursor

Carbonated amorphous calcium phosphate (CACP) precursors were precipitated by the wet chemical method at 5°C in the presence of poly(ethylene glycol) and carbonates. The nano carbonate‐substituted hydroxyapatite (HAp) was obtained after heat treat CACP precursors at a low temperature (800°C) for 3 h. The calcium phosphates were investigated by X‐ray diffraction, Fourier transform infrared spectroscopy, inductively coupled plasma, thermal gravimetric and differential thermal analysis, transmission electron microscopy, and scanning electron microscopy. The results show that calcium phosphate particles with a Ca/P molar ratio of 1.73 are AB‐type carbonate‐substituted HAp with about 50 nm in diameter.

Preparation of Nano- and Micrometric Ceftazidime Particles with Supercritical Anti-Solvent Technique

Nano- and microparticles of ceftazidime were prepared via a supercritical antisolvent (SAS) process. The influences of various processing parameters on the characteristics of the resultant particles were investigated. The experimental results revealed that the product's morphology closely correlated with the phase behavior of the mixtures in the precipitator during particle formation stage. Networked nanospheroids with narrow particle size distribution were produced when the precipitation was operated in either the compressed liquid region or in the supercritical region. However, the particulate products became less uniform as the precipitation was implemented near the critical region. While microspheroids were obtained as the precipitation was conducted in the superheated vapor region, dense films together with microparticles were formed in the vapor-liquid coexistence region. The untreated ceftazidime and the SAS precipitated samples were characterized with wide-angle X-ray scattering (WAXS), a differential scanning calorimeter (DSC), a thermogravimetric analyzer (TGA), and Fourier transform infrared spectrophotometry (FTIR). The analysis results indicated that the SAS-processed particles were amorphous and the water content was markedly reduced. Moreover, the molecular structure was still retained after the SAS processing.

Preparation and performance of nano silica/Nafion composite membrane for proton exchange membrane fuel cells

Composite membranes made from Nafion ionomer with nano phosphonic acid-functionalised silica and colloidal silica were prepared and evaluated for proton exchange membrane fuel cells (PEMFCs) operating at elevated temperature and low relative humidity (RH). The phosphonic acid-functionalised silica additive obtained from a sol–gel process was well incorporated into Nafion membrane. The particle size determined using transmission electron microscope (TEM) had a narrow distribution with an average value of approximately 11 nm and a standard deviation of ±4 nm. The phosphonic acid-functionalised silica additive enhanced proton conductivity and water retention by introducing both acidic groups and porous silica. The proton conductivity of the composite membrane with the acid-functionalised silica was 0.026 S cm −1, 24% higher than that of the unmodified Nafion membrane at 85 °C and 50% RH. Compared with the Nafion membrane, the phosphonic acid-functionalised silica (10% loading level) composite membrane exhibited 60 mV higher fuel cell performance at 1 A cm −2, 95 °C and 35% RH, and 80 mV higher at 0.8 A cm −2, 120 °C and 35% RH. The fuel cell performance of composite membrane made with 6% colloidal silica without acidic group was also higher than unmodified Nafion membrane, however, its performance was lower than the acid-functionalised silica additive composite membrane.

Synthesis and characterization of crystalline hexagonal bipods of zinc oxide

The preparation of nano- and submicrometre-sized one-dimensional (1D) zinc oxides (ZnOs) from zinc nitrate was performed by precipitation with urea in two types of solvents (water and water/polyol mixtures). The influence of different polyols (ethylene glycol, diethylene glycol and tetraethylene glycol) on the size of the final particles (length and diameter) is presented for the first time. As well as the influence of the solvents used, the ratio of water/polyol, temperature, pH and time of synthesis was correlated with the size and morphology of the final particles. In all cases crystalline ZnO was synthesized in the form of hexagonal bipods. The morphological and crystalline properties of the samples obtained were characterized by SEM, IR, and XRD.

A Pulse Combustion‐Spray Pyrolysis Process for the Preparation of Nano‐ and Submicrometer‐Sized Oxide Particles

The preparation of nano‐ and submicrometer particles using an integrated pulse combustion–spray pyrolysis process was investigated for the first time. Zinc oxide nanoparticles with average sizes ranging from 20 to 40 nm were synthesized using a salt precursor with a lower decomposition temperature than the pulse combustion (PC) temperature. Particles of a doped‐type oxide, gadolinium oxide‐doped with europium, were also produced from a precursor, whose decomposition temperature was higher than the PC temperature, and were observed to be ellipsoidal–toroidal in shape and submicrometer in size. The high‐intensity fluctuating pressures generated by PC and the precursor decomposition temperature are proposed as the reasons for the formation of either nanoparticles or aspherical particles. In addition, hot gas fluctuating flow in PC enhanced energy transfer, resulting in more crystalline particles, as compared with particles produced by conventional spray pyrolysis.

Preparation and Characterization of Nano structured Materials from Fly Ash: A Waste from Thermal Power Stations, by High Energy Ball Milling

The Class F fly ash has been subjected to high energy ball milling and has been converted into nanostructured material. The nano structured fly ash has been characterized for its particle size by using particle size analyzer, specific surface area with the help of BET surface area apparatus, structure by X-ray diffraction studies and FTIR, SEM and TEM have been used to study particle aggregation and shape of the particles. On ball milling, the particle size got reduced from 60 μm to 148 nm by 405 times and the surface area increased from 0.249 m2/gm to 25.53 m2/gm i.e. by more than 100%. Measurement of surface free energy as well as work of adhesion found that it increased with increased duration of ball milling. The crystallite was reduced from 36.22 nm to 23.01 nm for quartz and from 33.72 nm to 16.38 nm for mullite during ball milling to 60 h. % crystallinity reduced from 35% to 16% during 60 h of ball milling because of destruction of quartz and hematite crystals and the nano structured fly ash is found to be more amorphous. Surface of the nano structured fly ash has become more active as is evident from the FTIR studies. Morphological studies revealed that the surface of the nano structured fly ash is more uneven and rough and shape is irregular, as compared to fresh fly ash which are mostly spherical in shape.

Preparation and properties of magnetic nano‐ and microsized particles for biological and environmental separations

The paper presents a critical overview on magnetic nanoparticles and microspheres used as separation media in different fields of chemistry, biochemistry, biology, and environment protection. The preparation of most widely used magnetic iron oxides in appropriate form, their coating or encapsulation in polymer microspheres, and functionalization is discussed in the first part. In the second part, new developments in the main application areas of magnetic composite particles for separation and catalytical purposes are briefly described. They cover separations and isolations of toxic inorganic and organic ions, proteins, and other biopolymers, cells, and microorganisms. Only selected number of relevant papers could be included due to the restricted extent of the review.

Metal Oxide Nanocrystals: Building Blocks for Mesostructures and Precursors for Metal Nitrides

ABSTRACTSol-gel routes to metal oxide nanoparticles in organic solvents under exclusion of water represent a valuable alternative to aqueous methods. In comparison to the complex aqueous chemistry, nonaqueous processes offer the possibility to better understand and to control the reaction pathways on a molecular level, enabling the synthesis of nanomaterials with high crystallinity and well-defined and uniform particle morphologies. The manifold role of the organic species in providing the oxygen for the oxide formation and in controlling the crystal growth and the assembly properties makes it possible to tailor the morphological, structural and compositional characteristics of the final inorganic products.In addition to metal oxides with nearly spherical crystallite sizes in the range of just a few nanometers, also more complex morphologies such as nanowire bundles, nanorods or lamellar organic-inorganic hybrids of varying hierarchical complexity can be achieved in one step and without the use of any surfactants. The spherical nanocrystallites are on the one hand versatile building blocks for the fabrication of fully crystalline and ordered mesoporous materials and on the other hand suitable precursors for the synthesis of metal nitride nanoparticles.This proceeding provides an overview of the various oxidic nanoparticles synthesized via the nonaqueous and surfactant-free sol-gel approach, summarizes the most frequently found formation mechanisms, and offers some insight into the crystallization pathway of nanoparticles. Furthermore, the use of metal oxide nanoparticles as nanobuilding blocks for the preparation of nano- and mesostructures as well as their transformation into metal nitride nanocrystals will be discussed.

Preparation of nano disperse dyes from nanoemulsions and their dyeing properties on ultramicrofiber polyester

Six nano disperse dyes were prepared using corresponding O/W nanoemulsions which were obtained with sodium laurylsulphate and caprylic triglyceride. The average particle size of the dyes prepared were in the range of 110–130 nm. Exhaust dyeing using nano dyes resulted in low exhaustion yields of 17–26 % on regular polyester fiber and 28–38 % on ultramicrofiber polyester. The observed low exhaustion yields of nano disperse dye can be explained by the solubilization of dye particles into surfactant micelles as well as the high stability of the nanoemulsions, these might reduce the capacity of dye uptake onto the fibers. However, higher K/S values of dyeings with nano dyes on ultramicrofiber sites compared to those on regular polyester sites suggested their potential to be more efficient dyes for finer denier microfiber polyesters.

Preparation, characterization and ESR studies of bulk and nano sized pyrochlore La 2− xGd xZr 2O 7 ( x = 0.025, 0.05, 0.075 and 0.1)

Bulk and nano sized pyrochlore of composition La 2− x Gd x Zr 2O 7 ( x = 0.025, 0.05, 0.075 and 0.1) have been prepared by sol–gel method. They are characterized by powder X-ray diffraction and infrared spectroscopy. The sintering temperature influences the particle size of the sample. The room temperature powder ESR of La 1.95Gd 0.05Zr 2O 7 gave characteristic “U” spectrum. The influence of particle size on the ESR of Gd 3+ is investigated. Possible reason for the disappearance of “U” spectrum with increase in the particle size is given.

Preparation of nano‐ and microparticles through self‐assembly of azobenzene‐pendent ionomers

AbstractThe particle formation of azobenzene‐containing ionomers, through self‐assembly, in aqueous media (THF/H2O solvent) was studied. The ionomers were synthesized by copolymerization between azobenzene‐pendent methacrylate and methacrylic acid. It was revealed by UV–vis spectra and light scattering measurements that the extent of H‐aggregation of the azobenzene units first decreased, and then increased with increasing volume fraction of H2O of the solvent. The H2O fraction at which the extent of H‐aggregation began to increase became lower, when the copolymers contained more azobenzene units. Colloidal particles were prepared by slow addition of various concentrations of aqueous NaOH to the copolymer THF solutions. The hydrodynamic diameters of the particles obtained by the procedures were several hundreds of nanometer. When the azobenzene unit content in the copolymer was smaller, the diameters of the particles became smaller. When the colloidal particles dispersions were cast on a carbon sheet and dried, the particles aggregated and formed larger spherical particles, with diameters of several micrometers. The size of the particles obtained by the drying process became smaller, when higher concentrations of aqueous NaOH solutions were used. Therefore, the particle sizes were controlled by the azobenzene units content in the copolymers and the concentration of aqueous NaOH solutions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3913–3918, 2006

Preparation of Nano Y 2O 2S:Eu Phosphor by Ethanol Assisted Combustion Synthesis Method

Y 2O 2S:Eu nano crystallines were prepared by a new ethanol assisted combustion synthesis method using sulfurcontained organic fuel in an ethanol-aqueous solution. The as-prepared nanocrystallines were characterized by X-ray diffraction, transmission electron microscope, photoluminescence spectra and X-ray luminescence spectra. It is shown that the assistant fuel ethanol has the effect of decreasing the water needed, simplifying the experiment procedure by dissolving rare earth nitrate and sulfur-contained organic fuel into an even solution, and prompting the formation of rare earth oxysulfide by igniting firstly during heating that leads to combustion decomposition reaction. Y 2O 2S: Eu nano crystallines with strong photoluminescence and X-ray luminescence are obtained using thioacetamide as organic fuel. Mixtures of Y 2O 3: Eu and Y 2O 2S: Eu are acquired using thiourea as fuel, and the content of Y 2O 2S:Eu increases until reaches to about half of the Y 2O 3: Eu with the increasing amount of thiourea. Y 2O 2SO 4: Eu emerges when S/Y = 6 and increases with increasing thiourea amount.

Preparation of plate-like nano α-Al 2O 3 using nano-aluminum seeds by wet-chemical methods

Alumina particles with plate-like shape were prepared successfully by a wet chemical processes with nano-size aluminum additive. The seed-effect of nano-size aluminum and its effect on the final α-Al 2O 3 particle size and shape were investigated. TEM, XRD, XPS, Zeta potential and DSC/TG were used to observe the microstructure of the α-Al 2O 3 particle and analysis this wet chemical processes. It was found that aluminum additive not only helps to produce the nano-size plate-like α-Al 2O 3 particles effectively but also reduces the formation temperature of α-Al 2O 3.

Preparation and Characterization of Nano - Composite Electrodes by MOCVD

Preparation and Characterization of Nano - Composite Electrodes by MOCVD

Preparation of Nano Fe3O4/Polystyrene Composite Microspheres by in situ Polymerization

Carboxyl-functionalized magnetic microspheres were prepared by in situ polymerization of styrene and methyacrylic acid at 85°C in the presence of nano-Fe 3 O 4 in styrene, using lauroyl peroxide as an initiator. The effects of the surfactant, the weight ratio of magnetite to styrene, the amount of monomer and initiator on the polymerization reaction and microsphere properties were investigated in detail. Transmission electron microscopy showed the property of the surfactant on the surface of nano-Fe 3 O 4 determined the magnetite content and the distribution of the magnetite in the microspheres. The optimum conditions of the reaction were optimized. The adsorption result of bovine-γ IgG proves that the magnetic microspheres have a potential wide application in the biological field.

Preparation and PTCR Characteristics of Semiconductive Nano(Ba1-xSbx)TiO3 Ceramic PowderS by Hydrothermal Process

Semiconductive nano <TEX>$(Ba_{1-x}Sb_x)TiO_3$</TEX> powders were synthesized by the hydrothermal process and Sb was simultaneously doped in the hydrothermal condition. <TEX>$(Ba_{1-x}Sb_x)TiO_3$</TEX> powders obtained from optimum condition(at 20<TEX>$0^{\circ}C$</TEX> for 3hr) exhibited spherical shape, high purity and nano size. The PTCR characteristics was observed when 0.1 and 0.2 mole% Sb were added and sintered at over 130<TEX>$0^{\circ}C$</TEX> for 1 hour, respectively. And The ceramics exhibit the PTCR characteristics with a resistively jump <TEX>$ratio(<TEX>$\rho$</TEX>_{max}/<TEX>$\rho$</TEX>_{min})$</TEX> of about <TEX>$10^4$</TEX>. Also we found that PTCR characteristics were dependent on the microstructure.

Use of Dialkyldithiocarbamato Complexes of Bismuth(III) for the Preparation of Nano- and Microsized Bi2S3 Particles and the X-ray Crystal Structures of [Bi{S2CN(CH3)(C6H13)}3] and [Bi{S2CN(CH3)(C6H13)}3(C12H8N2)

A range of bismuth(III) dithiocarbamato complexes were prepared and characterized. The X-ray crystal structures of the compounds [Bi{S2CN(CH3)(C6H13)}3] (1) and [Bi{S2CN(CH3)(C6H13)}3(C12H8N2)] (2) are reported. The preparation of Bi2S3 particulates using a wet chemical method and involving the thermalysis of Bi(III) dialkyldithiocarbamato complexes is described. The influence of several experimental parameters on the optical and morphological properties of the Bi2S3 powders was investigated. Nanosized Bi2S3 colloids were obtained having long-term stability and showing a blue shift on the optical band edge; the presence of particles exhibiting quantum size effects is discussed. Morphological well-defined Bi2S3 particles were obtained in which the fiber-type morphology is prevalent.