The effect of alginate addition on the structure and morphology of hydroxyapatite/gelatin nanocomposites

A series of hydroxyapatite/gelatin/alginate nanocomposites with different amount of alginate were synthesized by a co-precipitation method. With the increase of alginate amount, a cross-linked alginate/gelatin polymer network formed, which induced a gradual red shift of organic absorption peaks in FT-IR analysis. TEM images indicated that the development of HAP nanocrystals in an aqueous gelatin/alginate mixture was highly influenced by the alginate content. On increasing alginate content, the dimensions of the crystals increased and their morphology changed from needle-like to long fiber-like, and at high alginate content, the crystals tended to aggregate in separate clusters. The results of the electron diffraction strongly indicated alginate promoted the preferential alignment in c direction of HAP nanocrystals. SEM results showed that high amount of alginate led to regular shape and large size of HAP crystals after the composites were calcined for 4 h at 600 °C.     

Synthesis and characterization of pure anatase TiO<Subscript>2</Subscript> nanoparticles

Pure anatase TiO₂ nanoparticles were synthesized by microwave assisted sol–gel method and further characterized by powder X-ray diffraction (XRD), energy dispersive x-ray analysis (EDAX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–Visible spectrophotometer, SEM images showed that TiO₂ nanoparticles were porous structure. The XRD patterns indicated that TiO₂ after annealed at 300 °C for 3 h was mainly pure anatase phase. The crystallite size was in the range of 20–25 nm, which is consistent with the results obtained from TEM images. Microwave heating offers several potential advantages over conventional heating for inducing or enhancing chemical reactions.     

Structure–property relationship of all-cellulose composites

Novel all-cellulose composite films were prepared by partly dissolving microcrystalline cellulose (MCC) powder in an 8% LiCl/DMAc solution. Cellulose solutions were precipitated and the resulting gels dried in a vacuum bag to produce films approximately 0.2–0.3 mm thick. X-ray diffraction (XRD) was used to characterise lateral crystal size and transmission electron microscopy (TEM) was employed to assess the morphology of the composites. During dissolution, the fibrous fragments of MCC were split into thinner cellulose fibrils and crystals were progressively broken down into thinner crystals. The composites were tested in tension and fracture surfaces were inspected by scanning electron microscopy (SEM). It was found that the mechanical properties and final morphology of all-cellulose composites was controlled by the rate of precipitation, initial cellulose concentration and dissolution time. The precipitation conditions were found to play a large role in the optimisation of the mechanical properties by limiting the amount of defects that were induced by differential shrinkage. All-cellulose composites were produced with a tensile strength up to 106 MPa and a tensile modulus up to 7.6 GPa.     

Novel and simple synthesis of ZnO nanospheres through decomposing zinc borate nanoplatelets

Spherical zinc oxide (ZnO) nanoparticles had been successfully synthesized through decomposing zinc borate nanoplatelets at high temperature. The resulted ZnO nanospheres were characterized by X-ray diffraction (XRD), which indicated that ZnO had the hexagonal structure. Field-emission-scanning electron micrographs (SEM) revealed that ZnO nanoparticles had perfect spherical shape with narrow size distribution (average diameters 50 nm). These nanoparticles showed a broad emission band centered at 438 nm using an excitation wave of 325 nm at room temperature. Moreover, the sample was characterized by N₂ adsorption-desorption and the pore size distribution showed a sharp peak at 3.1 nm.     

Preparation of zinc oxide nanorods by microwave assisted technique using ethylene glycol as a stabilizing agent

Zinc oxide nanorods have been synthesized by microwave assisted method using zinc nitrate, ethylene glycol and sodium hydroxide as a precursors. The material was characterized by XRD, SEM, EDAX and UV–Visible techniques. XRD analysis revealed all the relevant Bragg’s reflections for wurtzite (hexagonal phase) structure of zinc oxide. The average particle size was obtained 34 nm from the Williamson–Hall plot. The value of particle size determined from XRD was in good agreement with the SEM and TEM results. The direct optical band gap was found to be 3.13 eV.     

Synthesis and characterisation of SnO2 nano-single crystals as anode materials for lithium-ion batteries

Rutile structure SnO₂ nano-single crystals have been synthesized using tin (IV) chloride as precursor by the modified hydrothermal method. Controllable morphology and size of SnO₂ could be obtained by adjusting the concentration of the hydrochloric acid. The SnO₂ nanoparticles were characterised by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical methods. The SnO₂ nanoparticles as anode materials in lithium-ion batteries exhibit high lithium storage capacities. The reversible capacities are more than 630 mA h g^− 1.     

Synthesis of indium tin oxide (ITO) and fluorine-doped tin oxide (FTO) nano-powder by sol–gel combustion hybrid method

ITO and FTO nano-powders were synthesized employing a new route sol–gel combustion hybrid method using acetylene black as a fuel. The dried gels exhibited an auto-catalytic combustion behavior. ITO and FTO nano-powders with narrow size distribution were obtained at 750 °C. Crystal structures were examined by powder X-ray diffraction (XRD) and particle morphology as well as crystal size was investigated by scanning electron microscopy (SEM). The size of the nano-powder was found to be in the range of 16 nm to 33 nm.     

Synthesis and characterization of copper nanoparticles

Reduction of copper salt by sodium citrate/SFS and myristic acid/SFS leads to phase pure Cu nanoparticles. However, a similar reaction with hydrazine hydrate (HH) and sodium formaldehyde sulfoxylate (SFS) in polymer afforded only a mixture of Cu₂O and Cu. Copper nanoparticles so-prepared were characterized by UV-Visible spectroscopy, X-ray diffraction measurements (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Freshly prepared solutions showed an absorption band at about 600 nm due to surface plasmon resonance (SPR). XRD analysis revealed all relevant Bragg's reflection for fcc crystal structure of copper metal. The particle size by use of Scherrer's equation is calculated to be about 30 nm. TEM showed nearly uniform distribution of the particles in PVA.     

Synthesis of silver/poly (diallyldimethylammonium chloride) hybride nanocomposite

This paper presents a method for the preparation of silver nano-particles in poly (diallyldimethylammonium chloride) (PDDA) using N,N-dimethylformamide (DMF) as a medium has been performed successfully. A golden solution in its UV–vis absorption spectrum showed surface plasmon resonance absorption bands between 410 and 425 nm in solutions and at about 461 nm in a transparent film. The Ag/PDDA nano-composite was characterized by X-ray diffraction (XRD) measurement, transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform-infrared spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA). XRD showed the fcc crystal structure of the bulk Ag with particles of <22 nm in size similar to that is observed by TEM and PDDA is crucial to the formation of such silver nano-composite. SEM indicated uniform distribution of particles in the film. TGA confirmed enhanced thermal stability of the polymer.     

Utilization of biowaste eggshells to synthesize nanocrystalline hydroxyapatite powders

Nano hydroxyapatite (HA) powder was successfully synthesized from biowaste chicken eggshells. The nanopowders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), particle size distribution (PSD) analyzer, and Fourier transform infrared spectroscopy (FT-IR) techniques. Selected area electron diffraction (SAED) analysis during TEM showed the particles to be polycrystalline in nature. The resulting HA powder exhibited an average size of ~ 35 nm with a narrowly distributed particle size range from 5 to 90 nm. XRD and FT-IR analysis showed that the powders produced were of high purity. The present study provides a simple sol–gel precipitation method to obtain nano HA powders of high purity from biowaste chicken eggshells.     

Synthesis of polyaniline/Ag composite nanospheres through UV rays irradiation method

In this paper, a novel morphology of polyaniline (PANI)/Ag composite nanospheres was obtained through UV rays irradiation method. The structure and morphology of the product were characterized by Fourier transform infrared (FT-IR) spectrum, X-ray diffraction (XRD) pattern, Scanning electron micrograph (SEM) and Transmission electron microscopy (TEM) images, energy-dispersive X-ray (EDAX) analysis, and electron diffraction (ED), respectively. The results showed that the diameters of the PANI nanospheres and the Ag nanofilaments were 10–60 nm and 2–5 nm, respectively. UV rays played an important role for forming PANI nanospheres underpinned by Ag nanofilaments. A potential formation mechanism of PANI nanospheres underpinned by Ag nanofilaments was investigated.     

Synthesis of sphere-like Co3O4 nanocrystals via a simple polyol route

A simple polyol method was developed to synthesize uniform sphere-like Co₃O₄ nanocrystals in ethylene glycol. Powder X-ray diffraction (XRD) and electron diffraction (ED) showed that the as-prepared sample was indexed as the cubic spinel structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that the Co₃O₄ nanocrystals were spherical with the crystallite size in the range of 90-110 nm. Infrared spectra and Raman spectra confirmed the formation of the Co₃O₄ nanocrystals. The magnetic properties of the Co₃O₄ nanocrystals were measured by using a superconducting quantum interference device (SQUID) magnetometer, which showed that the as-prepared sample exhibited a tiny hysteresis loop with the magnetization value of 2.4 emu/g and the coercivity of 110 Oe.     

Hydrothermal synthesis of hexagonal ZnO clusters

Hydrothermal process was applied to synthesize zinc oxide nanocrystals. X-ray powder diffraction and scanning electron microscopy were used to analyze the crystal structure and surface morphology. XRD pattern analysis showed that the ZnO clusters are single hexagonal phase of wurtzite structure (space group P63 mc) with no impurity of Zn and Zn(OH)₂. Also, SEM images revealed that the size of a single ZnO crystal is between 200-500 nm in diameter and 2-5 μm in length. The influence of potassium iodide (KI) as a surfactant on the crystallinity of ZnO has been investigated.     

Evaluation and characterization of nanostructure hydroxyapatite powder prepared by simple sol-gel method

Many attempts have been focused on preparing of synthetic hydroxyapatite (HA), which closely resembles bone apatite and exhibits excellent osteoconductivity. Low temperature formation and fusion of the apatite crystals have been the main contributions of the sol-gel process in comparison with conventional methods for HA powder synthesis. This paper describes the synthesis of nano-HA particles via a sol-gel method. Nanocrystalline powder of hydroxyapatite (HA) was prepared using Ca(NO₃)₂·4H₂O and P₂O₅ by a simple sol-gel approach. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for characterization and evaluation of the phase composition, morphology and particle size of products. The presence of amorphous and crystalline phases in the as-dried gel precursor was confirmed by the evaluating technique. Single phase of HA was also identified in the heat treated powder by XRD patterns. SEM and TEM evaluations showed that the obtained powder after heat treatment at 600 °C was agglomerated and composed of nanocrystalline (25-28 nm) HA particles. Increasing the sintering temperature and time could cause decomposition of HA into β-tricalcium phosphate and calcium oxide. The prepared nanocrystalline HA is able to improve the contact reaction and the stability at the artificial/natural bone interface for medical applications.     

Solvothermal synthesis of hexagonal ZnO nanorods and their photoluminescence properties

Pure hexagonal ZnO nanorods were synthesized by low-temperature (90 °C) solvothermal treatment of zinc acetate in 40-80 wt.% hydrazine hydrate aqueous solutions. The products were characterized by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electronic microscopy (TEM), selected area electron diffraction (SAED), and room temperature photoluminescence (RTPL) spectra. They show a strong UV emission at around 380 nm upon excitation at 360 nm using a Xe lamp at room temperature. The influence on the quality of the nanorods was investigated while the content of the solvent changed. The as-synthesized ZnO nanorods are promising materials for nanoscale optoelectronic devices due to their excellent UV emission properties.     

Synthesis and characterization of CdS nanoparticles in polystyrene microfibers

We described the synthesis of hybrid fibers composed of cadmium sulfide (CdS) nanoparticles and polystyrene (PS) by an in-situ reaction method. Scanning electron microscopic (SEM) studies showed that the hybrid samples have a fiber-like morphology. Transmission electron microscopic (TEM) studies showed that CdS nanoparticles were embedded in PS fibers with a diameter from 10 to 20 nm. Fourier-transform infrared (FTIR), UV–vis spectrum and X-ray photoelectron spectra (XPS) were used to characterize the structure of the composite fibers. X-ray diffraction (XRD) results showed that a hexagonal CdS phase was obtained in the PS fibers.     

A simple route to lanthanum hydroxide nanorods

This letter first describes a facile, low-cost, solution-phase approach to the large-scale preparation of lanthanum hydroxide single crystal nanorods at 60 °C without any template and surfactant. X-ray diffraction (XRD) shows that the nanorods are of pure hexagonal structure. The size and morphology of the products were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Lanthanum hydroxide single crystal nanorods are with diameters of approximately 20 nm and lengths of 150-200 nm. The processes of formation and decomposition for the as-prepared lanthanum hydroxide nanorods were discussed.     

Effect of solvents on the synthesis of nano-size zinc oxide and its properties

The effect of the solvents on particle size and morphology of ZnO is investigated. The optical properties of nano ZnO were studied extensively. During this study, zinc oxalate was prepared in aqueous and organic solvents using zinc acetate and oxalic acid as precursors. The thermo-gravimetric analysis (TGA/DTA) showed formation of ZnO at 400 °C. Nano-size zinc oxide was obtained by thermal decomposition of aqueous and organic mediated zinc oxalate at 450 °C. The phase purity was confirmed by XRD and crystal size determined from transmission electron microscopy (TEM) was found to be 22–25 nm for the aqueous and 14 –17 nm in organic mediated ZnO. Scanning electron microscope (SEM) also revealed different nature of surfaces and microstructures for zinc oxide obtained in aqueous and organic solvents. The UV absorption spectra showed sharp absorption peaks with a blue shift for organic mediated ZnO, due to monodispersity and lower particle size. Sharp peaks and absence of any impurity peaks in photoluminescence spectra (PLS) complement the above observations.     

Electrodeposited hydroxyapatite coatings in static magnetic field

Uniform hydroxyapatite (HA) coatings were deposited electrochemically on titanium in magnetic fields. The structure and morphology of the deposited films were investigated by scanning electron microscopy, X-ray diffraction and transmission electron microscopy (SEM, XRD and TEM). It was found that the morphology of HA deposits could be altered by direction and intensity of applied magnetic field. Needle-like crystals formed when magnetic field was applied perpendicularly to electric field (B⊥ J), whereas spherical nanocrystals formed when magnetic and electric fields were in parallel (B||J). In addition, the nucleation rate of the HA crystals was proportional to the magnetic field intensity. Therefore, the resultant crystal size decreased with increasing magnetic field intensity.     

Characterization of cadmium sulfide nanorods prepared by the solvothermal process

Cadmium sulfide nanorods were successfully prepared from cadmium nitrate tetrahydrate and thiourea in ethylenediamine by 200 °C solvothermal reactions using hydroxyethyl cellulose (HEC) as a capping material. X-ray diffraction (XRD), selected area electron diffraction (SAED), and Raman spectroscopy showed that the products were hexagonal wurtzite CdS with the 1st and 2nd harmonic modes at 303.5 and 593.0 cm^− 1, respectively. The intensity ratios of the 2nd to 1st harmonic modes were increased with their aspect ratios, due to the great strength of exciton-phonon coupling. By using scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM) and fast Fourier transformation (FFT), the products were in the shape of nanoparticles in the HEC-free solution, and became nanorods with higher aspect ratios in the HEC-added solutions — especially with longer reaction time. These nanorods were single crystals with growth in the [001] direction.