Showing 29 results for Sol-Gel
F.s. Sayyedan, M.h. Fathi, H. Edris, A. Doostmohamadi, V.s., Mortazavi, F. Shirani,
Volume 33, Issue 3 (3-2015)
Abstract
The objective of this study was to synthesize glass ionomer–forsterite nanocomposite and study the effect of
incorporating forsterite nanoparticles to the ceramic part of glass ionomer cement in order to improve mechanical properties and
bioactivity. So, Forsterite nanoparticles were made by the sol-gel process using different weight percentages added to the ceramic
part of commercial GIC (Fuji II GC). X-ray diffraction (XRD) was used in order to characterize and determine grain size of the
produced forsterite nanopowder. In order to study the mechanical properties of the produced glass ionomer cement-forsterite
nanocomposite, the compressive strength (CS), three-point flexural strength (FS) and diametral tensile strength (DTS) of
specimens were measured. Statistical analysis was done by one Way ANOVA and differences were considered significant if
P‹0.05. The morphology of fracture surface of specimens was studied using scanning electron microscopy (SEM) technique.
Bioactivity of specimens was investigated by Fourier transitioned-infrared spectroscopy (FTIR), scanning electron microscopy
(SEM), and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The results of XRD analysis confirmed the
nanocrystalline and pure forsterite synthesis. According to the mechanical properties measurements, the optimum weight
percentages of forsterite nanoparticles for enhancement of CS, FS, and DTS were obtained equal to 3, 1 and 1 wt.%, respectively.
Statistical analysis showed that the differences between all the groups were significant (P<0.05). SEM images and results of the
ICP-OES and FTIR tests confirmed the bioactivity of the nanocomposite. Glass ionomer-forsterite nanocomposite containing 1 to
3 wt.%-forsterite nanoparticles can be a suitable candidate for dentistry and orthopedic applications due to the improvement of
mechanical properties and bioactivity.
S. Yazdkhasti, A. Monshi, A. Doostmohammadi,
Volume 34, Issue 4 (3-2016)
Abstract
With various features such as strong oxidation, biocompatibility and acceptable mechanical properties, titanium dioxide (TiO2) is among the materials that are frequently used in biological and medical applications. Nowadays, with the aim of increasing the efficiency of titanium dioxide and practical use of this material, doping it with elements such as silver, zinc and iron has been favored. In this study, Ag-TiO2 and ZnO-TiO2 nanoparticles were prepared by the sol–gel method and were evaluated and compared.In order to identify the present phases in the structure, X-ray diffraction analysis was used. Also for the characterization of the nanoparticles, Ultraviolet–visible spectroscopy (UV-Vis), Energy-dispersive X-ray spectroscopy (EDS), Field Emission Scanning Electron Microscope (FESEM) and Zeta Potential were used. Inaddition, the antibacterial activities of nanoparticles were investigated and compared. The results showed that sol-gel method could successfully produce nanoparticles of Ag-TiO2 and ZnO-TiO2 with the expected combination. The investigation of antibacterial properties of these particles revealed that at lower inhibitory concentrations, Ag-TiO2 composition has a higher antibacterial activity than ZnO-TiO2 one.
A. Abdolahi, M. R. Saeri, F. Tirgir, A. Doostmohammadi, H. Sharifi,
Volume 35, Issue 1 (6-2016)
Abstract
In this study, NBG was successfully achieved through a sol-gel technique, and to further improve its dispersibility, a crylate coupling agent was coupled onto the surface of the NBG. The 3-(Trimethoxysilyl)Propylmethacrylate coupling agent was used to the surface modification of the synthesized NBG by a wet-chemical method in a dynamic inert nitrogen atmosphere. The surface properties of the biomaterials before and after modification were characterized and compared using FTIR and AFM techniques. The characteristic peaks in FTIR spectra indicated that –CH2, –CH3 and C=O groups appeared on the surface of modified NBG, and also, AFM analysis revealed that the dispersibility of surface modified NBG was improved, significantly. The above results proved that the desired groups of 3-(Trimethoxysilyl)Propyl methacrylate had been covalently bonded onto the surface of NBG. Besides, a nanocomposite scaffold was synthesized using the synthesized NBG and polyurethane foam as raw materials. The morphology of pores, porosity contents, compress strength and bioactivity of the scaffold were studied. The results showed that the biological scaffolds for use in bone tissue engineering with the basic requirements (90% porosity and 200-600 μm pore diameter) were successfully prepared. The polymer component had no effect on the relationship between the scaffold pores and bioactivity of bioglass nanoparticles. Improvement of compressive strength and proper bioactivity of the resulted scaffold showed that it is an acceptable candidate for biomaterials applications.
M. Rezazadeh, M.r. Saeri, F. Tirgir Malkhlifeh, A. Doostmohammdi,
Volume 35, Issue 2 (9-2016)
Abstract
The aim of the present study is to study the effects of adding diopside (CaMgSi2O6) as well as silica sulfuric acid nanoparticles to ceramic part of glass ionomer cement (GIC) in order to improve its mechanical properties. To do this, firstly, diopside (DIO) nanoparticles with chemical formula of CaMgSi2O6 were synthesized using sol-gel process and then, the structural and morphological properties of synthesized diopside nanoparticles were investigated. The results of scanning electron microscopy (SEM) and particle size analyzing (PSA) confirmed that synthesized diopside are nanoparticles and agglomerated. Besides, the result of X-ray diffraction (XRD) analyses approved the purity of diopside nanoparticles compounds. Silica sulfuric acid (SSA) nanoparticles are also prepared by chemical modification of silica nanoparticles by means of chlorosulfonic acid. Fourier transform infrared spectroscopy (FTIR) technique was used to find about the presence of the (SO3H) groups on the surface of silica sulfuric acid nanoparticles. Furthermore, various amounts (0.1, 3 and 5 wt.%) of diopside and silica sulfuric acid nanoparticles were added to the ceramic part of GIC (Fuji II GIC commercial type) to produce glass ionomer cement nanocomposites. The mechanical properties of the produced nanocomposites were measured using the compressive strength, three-point flexural strength and diametral tensile strength methods. Fourier transform infrared spectroscopy technique confirmed the presence of the (SO3H) groups on the surface of silica nanoparticles. The compressive strength, three-point flexural strength and diametral tensile strength were 42.5, 15.4 and 6 MPa, respectively, without addition. Although adding 1% silica solfonic acid improved nanocomposite mchanical properties by almost 122%, but maximum increase in nanocomposite mechanical properties was observed in the nanocomposites with 3% diposid, in which 160% increase was seen in the mechanical properties.
M. Bahrami, G.h. Borhani, S.r. Bakhshi, A. Ghasemi,
Volume 35, Issue 3 (12-2016)
Abstract
Organic–inorganic hybrid coatings were prepared by sol–gel method and deposited on aluminum alloy 6061. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy (SEM) were used for structural study of the hybrid coatings. Adhesive strength of sol–gel coatings to the substrate was evaluated quantitatively and qualitatively. Corrosion behavior of the samples was studied by cyclic potentiodynamic and linear polarization tests. Results showed that adhesion strength of the coatings to the substrates was increased with increasing tetrapropoxide of zirconium (TPOZ) and cerium content. Corrosion tests showed that corrosion current density of coated samples were decreased three to seven orders of magnitude in comparison with uncoated aluminum alloy 6061. Decreasing in corrosion current density and increasing in polarization resistance was observed by increasing zirconia and cerium content. Unlike the uncoated aluminum alloy 6061, the crack-free coatings did not show pitting tendency.
S. Shirinparvar, R.s. Razavi, F. Davar, M.r. Loghman-Estarki, S. Ghorbani,
Volume 35, Issue 4 (2-2017)
Abstract
In this research, the nanopowders of lanthanum and neodymium co-doped yttria were synthesized by sol-gel combustion method. Citric acid and glycine were used as the gel maker and fuel respectively. The effect of molar ratio of citric acid to glycine on the grain size and morphology was evaluated. The optimized products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), transmission electron microscope (TEM), UV–visible (UV–Vis), thermal gravimetric-differential thermal analysis (TG/DTA), and Fourier transform infrared spectrometer (FTIR). The optimized products which are synthesized with a molar ratio citric acid to glycine 1.06:1.06 have an average grain size of 30-40nm with spherical morphology, and without agglomeration. Also, their band gap is 3.29eV.
S. Alamolhoda, S. M. Mirkazemi, T. Shahjooyi, N. Benvidi,
Volume 36, Issue 2 (9-2017)
Abstract
In this research, nickel ferrite nanoparticles were synthesized by sol-gel auto-combustion route, and the effect of calcination temperature on phase constituents, magnetic properties and microstructure of the synthesized nanoparticles was evaluated using X-ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM) and Scanning Electron Microscopy (SEM). XRD results were submitted to quantitative analysis. Microstructural studies and crystallite size calculations showed formation of nanoparticles. XRD results showed that the combustion product consisted of NiFe2O4, α-Fe2O3, NiO, and FeNi3 phases. FeNi3 was eliminated by calcination, and the amounts of NiO and α-Fe2O3 were modvlated by changing in calcination temperature. Saturation magnetization changed from 37emu/g in combustion product to 30emu/g by calcination at 600°C, due to decomposition of FeNi3 magnetic phase and formation of higher amount of antiferromagnetic hematite phase. Also, the coercivity values increased, that could be due to increasing the amount of nickel ferrite phase and eliminating FeNi3 phase. Saturation magnetization reached to 43emu/g in calcinated sample at 1000°C due to the reaction between hematite and NiO phases that led to formation of higher amount of nickel ferrite to 43emu/g. Coercivity value dropped out to 127Oe by calcination at 1000°C, the reason of which could be incresing of particle size and formation of multi domain magnetic particles.
S. E. Mousavi Ghahfarokhi, F. Bazdar, I. Kazeminezhad,
Volume 36, Issue 2 (9-2017)
Abstract
In this paper, Ni-doped lead hexaferrites (PbFe12-xNixO19) nanoparticles with x = 0.2 were prepared by sol- gel method. Then, the effect of annealing temperature on its structural, magnetic and dielectric properties was studied. First, the dryed gel was evaluated by Thermogravimetry-Differential Thermal Analysis (TG/DTA) and then, the structural morphology, magnetic and dielectric properties of samples have been characterized by Fourier Transform Infrared (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Vibrating Sample Magnetometer (VSM) and LCR meter. The results of x-ray diffraction patterns show that by increasing annealing temperature up to 800 °C, PbFe11.8Ni0.2O19 phase percentage in the samples increases. Also, by increasing annealing temperature, the magnetization increases because the unwanted phases disappear and pure and single-phase lead hexaferrite are formed. By increasing frequency, first the AC electrical conductivity of the samples decreases and then increases. These variations have been explained by Maxwell- Wanger model. The result measurements show that the best sample is PbFe11.8Ni0.2O19 with annealing temperature of 800 °C for 3 h.
A. Rostamnejadi, M. K. Esmaeilzadeh,
Volume 36, Issue 3 (11-2017)
Abstract
In this research, nanoparticles of La0.8Sr0.2MnO3 with mean crystallite size of 20 nm have been prepared by sol gel method. The sample has been characterized by X-Ray Diffraction (XRD) using Rietveld refinement, Field Emission Scanning Electron Microscope (FESEM) and Fourier Transform Infrared (FTIR) spectroscopy. The static magnetic properties such as saturation magnetization, effective magnetic moment and ferromagnetic phase fraction of the nanoparticles are determined by different techniques using magnetic hysteresis loop at room temperature. The magnetic dynamic properties of crystalls are studied by measuring AC magnetic susceptibility versus temperature at different frequencies. Néel-Brown, Vogel-Fulcher, critical slowing down models and empirical parameters are used to distinguish between superparamagnetic and superspin glass behaviour in the nanoaprticles. By fitting the experimental data with the models, relaxation time, critical view, magnetic anisotropy energy and effective magnetic anisotropy constant have been estimated. The obtained results support the presence of interacting superparamagnetic behaviour between magnetic nanoparticles of La0.8Sr0.2MnO3.
S. Daneshvar E Asl, S. K. Sadrnezhaad,
Volume 36, Issue 3 (11-2017)
Abstract
TiO2/MWCNT nanocomposite thin films containing different percentages of multi-walled carbon nanotubes were coated on fluorinated tin oxide substrates by sol-gel dip coating method. Results of X-ray diffraction analysis indicated that the crystal structure of the coatings was anatase TiO2. It was also understood that the size of crystallites reduced with CNT but structural properties and equilibrium phase remain intact. Field emission scanning electron microscope images showed that CNTs dispersed uniformly among 45 nm spherical TiO2 particles of close relations. These images also showed that CNT promoted cracks on the coated surface. Results of the UV-Vis spectroscopy showed that the visible light range adsorption increased with CNT and the absorption edge did not significantly differ with the pure TiO2 layers.. Results of the photoluminescence spectroscopy revealed that the presence of CNT could reduce the pair electron–electron holes recombination which is considered totally undesirable.
Z. Talebi, Mahin Karimi, Negar Habibi,
Volume 37, Issue 1 (6-2018)
Abstract
In the present study, silica aerogel was evaluated by a two-step catalytic process at the ambient pressure drying, under different synthesis conditions. The effects of the catalyst and water content in the hydrolysis step on the physical properties of silica aerogel, including density, porosity and shrinkage, were investigated. The results showed that increasing the water content in the hydrolysis step increased the shrinkage of gel network and density of obtained aerogel. Moreover, in the presence of insufficient water, NH4OH as the condensation catalyst in the gel formation step was more effective on the physical properties of silica aerogel, as compared to HCl as thehydrolysis catalyst; Moreover, the increase in the NH4OH content led to lower density and higher porosity. On the other hand, NH4OH effect on the physical properties of silica aerogel was not noticeable in the presence of enough water content. In the NH4OH/HCl molar ratio of 6, the best silica aerogel sample was obtained with the density of 0.214 g/cm3, porosity of 90% and shrinkage of 23%
M. Hajfarajzadeh, A. Eshaghi, A. Aghaei,
Volume 37, Issue 4 (3-2019)
Abstract
A TEOS-GPTMS nano-hybrid thin film was deposited on the polymethyl methacrylate (PMMA) substrate by a sol-gel dip coating method. Morphology, roughness and surface chemical bonding of the thin films were evaluated by X-ray diffraction (XRD), field emission scanning electron microscopy(FE-SEM), atomic force microscopy, and Fourier transform infrared spectroscopy methods, respectively. UV-vis spectrophotometer was used to measure the transmittance spectra of the samples. Also, the adhesion and hardness of the coatings were investigated using pencil hardness the adhesion tape test and the test, respectively. XRD results proved that the thin film had an amorphous structure. Also, FE-SEM images indicated that addition of GPTMS to the TEOS yielded a crack-free thin film. Based on the UV-vis spectroscopy results, the transmittance of the polymer substrate in the visible region was increased by the deposition of the nano-hybrid coating. Moreover, the hardness of the PMMA substrate was increased from 3H to 6H by the deposition of the nano-hybrid thin film. Also, tape test confirmed the high adhesion of the nano-hybrid thin film on the PMMA substrate. Consequently, the transparent organic-inorganic GPTMS-TEOS hybrid coating can be used as a scratch resistant coating on the PMMA substrate.
M. Afrashi, D. Semnani, Z. Talebi,
Volume 38, Issue 2 (9-2019)
Abstract
In this study, adsorption of fluconazole on silica aerogel was performed successfully by the immersion method in the 1% solution of fluconazole-ethanol at the ambient condition and without using the supercritical method. The hydrophobic and hydrophilic silica aerogels were synthesized by the two-stage sol-gel method and dried at the ambient temperature. This method had most of drug loading at 24 h. It was 1.92% and 1.98% for the hydrophilic and hydrophobic silica aerogels, respectively. Physical properties of the synthesized aerogels were studied by the nitrogen absorption and desorption tests. The presence of fluconazole and the chemical structure of the samples were determined by fourier-transform infrared spectroscopy (FTIR). As well, the loading and release of the drug were investigated using a spectrophotometer. The results showed the structure of the synthesized aerogels had a pore diameter of 6-8 nm and a surface area of about 800-100 m2/g. The study of the drug release also revealed that the release rate of fluconazole in the hydrophilic silica aerogel was higher than that of the hydrophobic sample.
N. Alirezaei Varnosfaderani, S. E. Mousavi Ghahfarokhi, M. Zargar Shoushtari,
Volume 38, Issue 3 (12-2019)
Abstract
In this paper, W-type SrCo2Fe16O27 hexaferrite nanostructures were synthesized by sol-gel auto-combustion method. Effect of annealing temperature on the structural, magnetic and optical properties of these SrCo2Fe16O27 nanostructures was investigated. In order to determine the annealing temperature of samples, the prepared gel was examined by thermo-gravimetric and differential-thermal analyses. Morphology and crystal structure of the prepared samples were characterized by field emission scanning electron microscopy and X-ray diffraction pattern. Based on X-ray diffraction results, at annealing temperature of 1000 °C, the maximum amount of main phase formed. A planar morphology was spectroscopy for the synthesized samples through scanning electron microscope images. Fourier transform infrared analysis was used to confirm the synthesis of the main properties obtained of samples were measured by the vibrating sample magnetometer and the results showed that by increasing temperature, magnetic saturation increases. Moreover, optical properties of samples were investigated by ultraviolet–visible absorption and photoluminescence spectroscopies. The result of measurements of the energy gap approximately is same in the ultraviolet- visible and photoluminescence spectroscopes and also the energy gap is constant with increasing temperature.
F. Mohammadi Bodaghabadi, M. R. Loghman Estarki, M. Ramazani, A. Alhaji,
Volume 38, Issue 3 (12-2019)
Abstract
In this research, synthesis of lithium fluoride (LiF) nanoparticles by fluorolytic sol-gel method has been studied. Moreover, the effect of lithium ion to fluorine source molar ratio and calcination temperature on particle size and phase of LiF nanoparticles were investigated. Lithium acetate (C2H3LiO2), trifluoroacetic acid (TFA), ethylene glycol monobutyl ether and oleic acid were used as sources of Li+ and F- ions, solvent and growth inhibitor, respectively. Thermal and X-ray diffraction (XRD) analyses as well as field emission scanning electron microscopy (FESEM) were used to investigate thermal behavior of the primary gel and to determine the phase and morphology of samples, respectively. The results showed that the 2: 1 molar ratio of Li+/ TFA and the calcination temperature of 400 °C result in LiF nanoparticles with a mean particle size of 80-100 nm.
A. Karimian, Kalantar,
Volume 39, Issue 1 (5-2020)
Abstract
In this research, barium calcium hexaferrite (Ba1-xCaxFe12O19 , 0≤x£1) nanoparticles were synthesized through a sol-gel combustion method. The dried gel samples were then calcined at 950ºC for 4:30h. The phase and microstructural evolution of calcined samples were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results revealed formation of calcium -barium hexaferrite phase with a small amount of hematite as a secondary phase. The average particle size is between 60-100 nm and the particle morphology is hexagonal or plate like structure. Results of a vibrating sample magnetometer (VSM) showed that the sample with x=0.4, exhibited the lowest value of saturation magnetization in comparison with others. This could be due to structural heterogeneity and presence of higher amounts of non- magnetic phases (BaFe2O4 and Fe2O3) in this sample compared to others. The results of sensory testing in acetone gas showed that the barium-calcium hexaferrite sample with x=0.2 had the highest sensitivity (0.28) and shortest response (15s) at a concentration of 900 ppm and a temperature of 200 °C despite of the long recovery time.
F. Davar, Z. Enteshari,
Volume 39, Issue 1 (5-2020)
Abstract
In this research, Zinc oxide nanoparticles with semi-spherical morphology were synthesized by modified sol-gel method using rosemary extract as a stabilizing agent. The effect of the amount of rosemary extract and calcination temperature on size and shape of the particles was investigated. The samples were characterized by X-ray diffraction (XRD), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and elemental analysis (EDX). X-ray diffraction results showed hexagonal structure (wurtzite phase) of zinc oxide. According to the SEM results semi-spherical nanoparticles of 18 nm in size were obtained using 75 ml of rosemary extract. The photocatalytic activity of the modified ZnO nanoparticles was investigated for degradation of the methylene blue dye solution. The results showed 96.87% of dye degradation in the 135 min that confirmed suitable efficiency of as-synthesized nanoparticles in the photocatalytic degradation process of dyes.
M. Farhadian, K. Raeissi, M. A. Golozar,
Volume 39, Issue 2 (8-2020)
Abstract
This work is focused on the effect of amorphous SiO2 addition on the phase transformation and microstructural evolution of ZrO2 particles. Considering the structural similarities between the amorphous ZrO2 and its tetragonal structure, XRD results showed initial nucleation of metastable tetragonal ZrO2 from its amorphous matrix upon heat treatment. This metastable phase is unstable in pure ZrO2 sample and transforms to a stable monoclinic phase at around 600 oC. However, addition of amorphous SiO2 to ZrO2 structure causes metastable tetragonal phase to remain stable up to around 1100 oC. The temperature range for stability of metastable tetragonal ZrO2 structure increased from about 150 oC in pure ZrO2 particles to around 500 oC in ZrO2-10 mol.% SiO2 composite powders. A further increase in SiO2 content up to 30 mol.% did not change the stabilization temperature range but the average particle size reduced around 1.6 times compared to pure ZrO2 particles. Stabilization of metastable tetragonal ZrO2 explained by constrained effect of SiO2 layer surrounding zirconia nuclei. The thickness of this SiO2 layer enhanced by increasing SiO2 content which limited the growth of ZrO2 nuclei resulting in finer particle sizes.
M. Ghorbani, H. Khorsand,
Volume 40, Issue 2 (9-2021)
Abstract
Strontium hexaferrite M-type nanoparticles doped with La and Cu (SrFe12-xCuxO19-Sr1-xLaxFe12-xCuxO19) with different mole fractions (x=0.1-0.2-0.3-0.4-0.5) synthesized by self-combustion sol-gel technique. Firstly, a gel of metal nitrates with the above-mentioned mole fractions were fabricated and the obtained powder was cured at 950°C. Microstructural properties and the morphology of the compounds were investigated by employing X-ray diffraction (XRD) and scanning electron microscopy (SEM). Also, in order to investigate the magnetic properties, Vibrating Sample Magnetometer (VSM) was used. SEM images revealed that the particles had an average size of about 100 nm. Cu2+ ions were substituted with Fe3+ ions within the crystalline sites of SrFe12O19 structure. It was shown that the lattice parameter (a) remained approximately unchanged with an increase in Cu-dopped while the lattice parameter (c) decreased with increasing the mole fraction (x). By using VSM hysteresis diagrams, it was observed that the saturated magnetization and coercive force increased with the addition of La; this was attributed to the variation in the distribution of ions and the shape anisotropy of the nanoparticles. These significant changes in the magnetic properties were for the sample with the composition of Sr1-xLaxFe12-xCuxO19 and SrFe12-xCuxO19, for the x=0.1 and x=0.5, respectively.
A. Azimi-Fouladi , S.a. Hasanzadeh-Tabrizi,
Volume 41, Issue 2 (11-2022)
Abstract
Water pollution is one of the big problems of human societies, and the need to find new ways to remove these pollutants has been given much attention in recent years. One of the methods is the use of photocatalysts. In this research, TiO2 and TiO2-CdO nanoparticles were prepared by a sol-gel method as nano photocatalysts. The produced samples have been used to degrade methylene blue under UV light. To characterize the prepared samples, X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), X-ray Energy Diffraction Spectroscopy (EDS), and Ultraviolet-Visible Spectroscopy (UV-Vis) were used. Microstructural results revealed nanoparticles with dimensions of 18 to 32 nm. XRD results showed that the main phase formed was the anatase. TiO2-4 wt.% CdO nanocomposite showed more photocatalytic activity compared to pure TiO2. Also, the effect of pH, irradiation time, and amount of powder on photocatalytic activity was investigated. The results showed that at pH=9, time of 75 min, and using 0.02 g TiO2-4 wt.% CdO photocatalyst, the maximum photocatalytic activity of about 92 % was obtained.
