An Experimental Study on Synthesis and Characterization of Silica Nanoparticles Prepared by Sol-Gel Method

2007 ◽  
Vol 553 ◽  
pp. 245-251
Author(s):  
Ali Shokuhfar ◽  
Tolou Shokuhfar ◽  
M. Ghazinejad ◽  
R. Babazade ◽  
S. Tabatabae
Keyword(s):  
Electron Microscopy ◽  
Silica Nanoparticles ◽  
Size Distribution ◽  
Sol Gel ◽  
Sio2 Nanoparticles ◽  
Industrial Applications ◽  
Silica Particles ◽  
Narrow Size Distribution ◽  
Molar Ratios ◽  
Transmission Electron

Monodispersed nanometer-sized particles proved to be very important and advantageous in many industrial applications. One of the notable groups of these particles is silica (SiO2) nanoparticles which are widely utilized in developing numerous products such as electrical and thermal insulators, humidity sensors, varnish, etc. Since the quality of some of these products depends highly on the purity and size distribution of the silica particles, it is necessary to produce silica nanoparticles of narrow size distribution and very high purity. In this research silica nanoparticles, with a relatively narrow size distribution, have been synthesized via the hydrolysis reaction of tetraethoxisilane (TEOS) in the solution of deionized water and ethanol (C2H5OH), and in the presence of ammonia (NH3) as a catalyst. The nature, morphology and the size of the silica particles has been studied using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray diffraction. Results indicate that the morphology, structure and the diameter of silica particles depend strongly on the molar ratios of the reactants.

Characterization of Nanostructured Silica as Carrier for Insecticides Deltamethrin, Pyriproxyfen, and Chlorpyrifos and Testing the Insecticidal Efficacy Against Trogoderma granarium (Coleoptera: Dermestidae) Larvae

2019 ◽  
Vol 113 (1) ◽  
pp. 511-517
Author(s):  
Masumeh Ziaee ◽  
Asgar Babamir-Satehi
Keyword(s):  
Electron Microscopy ◽  
Silica Nanoparticles ◽  
Sol Gel ◽  
Sem Analysis ◽  
Efficient Treatment ◽  
Trogoderma Granarium ◽  
Transmission Electron ◽  
Insecticidal Efficacy ◽  
Sol Gel Process ◽  
Nanostructured Silica

Abstract Nanostructured silica can be used as a carrier of pesticides to enhance stability and controlled release of agrochemicals with an effective concentration on target pests. Silica nanoparticles (SNPs) were synthesized by sol–gel process and employed as a carrier of three different insecticides including deltamethrin, pyriproxyfen, and chlorpyrifos. The SNPs were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis and the insecticides-loaded in SNPs were characterized by transmission electron microscopy (TEM). The toxicity of insecticides alone and loaded in SNPs was evaluated against small and large larvae of Trogoderma granarium Everts on concrete surfaces. The immediate mortality was counted after 1, 3, and 7 d of exposure, and then surviving individuals were transferred to untreated surfaces for seven more days, with delayed mortality was recorded. Small larvae were more susceptible than large ones on all insecticide treatments. In addition, insecticides loaded in silica nanoparticles were more effective when compared with application of the insecticides alone. For immediate mortality, deltamethrin loaded in SNPs was the most efficient treatment causing 70.5% mortality on small and 55.5% mortality on large larvae after 7 d of exposure to the highest concentration. Pyriproxyfen loaded in SNPs caused low immediate mortality, but the mortality increased in delayed count indicated that the insecticide could control the larvae even after they have been removed from treated surfaces. It can be concluded that loading insecticides in SNPs could significantly increase their insecticidal efficiency, but this increase was compound-dependent.

Silica and Silane Coupling Agent for in Situ Reinforcement of Acrylonitrile-Butadiene Rubber

1999 ◽  
Vol 72 (1) ◽  
pp. 119-129 ◽  
Author(s):  
K. Murakami ◽  
S. Osanai ◽  
M. Shigekuni ◽  
S. Iio ◽  
H. Tanahashi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Silica Particles ◽  
Butadiene Rubber ◽  
Acrylonitrile Butadiene Rubber ◽  
In Situ Silica ◽  
Transmission Electron ◽  
Dispersion Agent ◽  
The Relationship

Abstract In situ silica reinforcement for the acrylonitrile-butadiene rubber (NBR) vulcanizates, which were premixed with a conventional silica (VN-3) and γ-mercaptopropyltrimethoxysilane (γ-MPS), was achieved by the sol-gel reaction of tetraethoxysilane (TEOS) using ethylenediamine. It was observed that the reinforcement efficiency tended to increase with the increase of mechanically premixed conventional silica. From the observations of transmission electron microscopy and scanning electron microscopy, the simultaneous use of VN-3 and γ-MPS was found to promote the formation of large silica particles and clusters with a relatively good dispersion by the sol-gel reaction of TEOS in the NBR vulcanizate. The results of hysteresis measurements supported this promotion. It was considered to be due to the surface modification of VN-3 by the sol-gel reaction of TEOS and the presence of γ-MPS which worked as a dispersion agent for silica particles. The relationship between the mechanical properties and the morphology of the in situ silica filled vulcanizates is discussed.

Microstructural characteristics and photoluminescence performance of nanograined thermally treated CeO2-TiO2 xerogels

2007 ◽  
Vol 22 (5) ◽  
pp. 1182-1187
Author(s):  
Amita Verma ◽  
A.K. Srivastava ◽  
N. Karar ◽  
Harish Chander ◽  
S.A. Agnihotry
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
Sol Gel ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Crystallite Sizes ◽  
Thermally Treated

Nanostructured thermally treated xerogels have been synthesized using a sol-gel process involving cerium (Ce) chloride heptahydrate and titanium (Ti) propoxide mixed in different Ce:Ti molar ratios. Structural features of the xerogels have been correlated with their photoluminescence (PL) response. The crystallite sizes in the samples lie in the nanorange. The x-ray diffraction and transmission electron microscopy results have confirmed the coexistence of CeO2 and TiO2 nanocrystallites in these xerogels. In general, a decrease in the CeO2 crystallite size and an increase in the TiO2 crystallite size are observed in the xerogels as a function of Ti content. Scanning electron microscopy results have evidenced the evolution of ordered structure in the xerogels as a function of TiO2 content. Although both of the phases (CeO2 and TiO2) have exhibited PL in ultraviolet and visible regions, the major luminescence contribution has been made by the CeO2 phase. The largest sized CeO2 crystallites in 1:1 thermally treated xerogel have led to its highest PL response. PL emission in the xerogels is assigned to their nanocrystalline nature and oxygen vacancy-related defects.

Functionalized Silicate Supported TiO2-ZnO Nanocomposite Film and its Application in Simultaneous Photocatalytic Degradation of Toxic Molecules

2013 ◽  
Vol 764 ◽  
pp. 255-265 ◽  
Author(s):  
R. Dhanalakshmi ◽  
A. Pandikumar ◽  
R. Ramaraj
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Potential Candidate ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Molar Ratios ◽  
Amine Functionalized ◽  
Transmission Electron

The TiO2-ZnO nanocomposite materials ((TiO2-ZnO)NCM) with different molar ratios (Ti:Zn) was synthesized by chemical route and dispersed in functionalized silicate sol-gel matrix (Silicate/(TiO2-ZnO)NCM)). The as prepared Silicate/(TiO2-ZnO)NCM were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The dispersion of the small amount of (TiO2-ZnO)NCM in silicate sol-gel matrix paves the way for the preparation of solid-state thin film photocatalyst which is advantageous for the separation of the catalyst from solution, the substrates and the reaction products. The simultaneous photoinduced oxidation of methylene blue (MB) dye and reduction of Cr (VI) to Cr (III) was examined at different amine functionalized silicate sol-gel embedded (TiO2-ZnO)NCM films. The (TiO2-ZnO)NCM dispersed into the amine functionalized silicate sol-gel matrix (TPDT) exhibited enhanced photocatalytic activity when compared to the (TiO2-ZnO)NCM without the silicate sol-gel. The functionalized silicate sol-gel supported (TiO2-ZnO)NCM is a potential candidate for energy conversion and environment remediation and cleaning applications.

scholarly journals Size-Selective Precipitation and Aggregate Reduction of FePt-Based Nanoparticles

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Pharunee Sarmphim ◽  
Pongsakorn Jantaratana ◽  
Chitnarong Sirisathitkul
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Data Storage ◽  
Ultrasonic Power ◽  
Narrow Size Distribution ◽  
Selective Precipitation ◽  
Density Data ◽  
Iron Platinum ◽  
Transmission Electron ◽  
By Products

Magnetic nanoparticles with a narrow size distribution are desirable for applications in ultra-high density data storage and biomedicine. In this work, the size-selective precipitation and aggregate reduction were combined to classify superparamagnetic iron platinum- (FePt-) based nanoparticles. The size-selective precipitation was implemented with the variation in the amount of ethanol. In the first condition, the ratio of ethanol-to-nanosuspension of 3 : 4 was used in the precipitation twice. By contrast, the second condition employed the ratios of ethanol-to-nanosuspension of 4 : 4 in the first precipitation and 5 : 4 in the second precipitation. The first precipitation successfully sorted out the aggregated particles, and the second precipitation collected particles with a narrow size distribution. The increase in ethanol enhanced the monodispersity of nanoparticles as shown by transmission electron microscopy (TEM) images and size distribution curves. In addition, large aggregated by-products from the precipitation stage were sonicated with the addition of surfactants. The increase in ultrasonic power reduces the aggregation, but the longer sonication led to an uneven distribution.

scholarly journals Synthesis of ZnO-CuO Nanocomposite Aerogels by the Sol-Gel Route

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Rula M. Allaf ◽  
Louisa J. Hope-Weeks
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Copper Nitrate ◽  
Zinc Hydroxide ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Composite Aerogels ◽  
Copper Composite

The epoxide addition sol-gel method has been utilized to synthesize porous zinc-copper composite aerogels in the zinc-to-copper molar ratios of 50 : 50 to 90 : 10. A two-step mixing approach has been employed to produce aerogels composed of nano- to micrometer sized particles. The aerogels were characterized by ultrahigh resolution scanning electron microscopy, transmission electron microscopy, and powder X-ray diffraction. The as-synthesized aerogels had a thin flake- or petal-like microstructure comprised of clustered flakes on two size scales; they were identified as being crystalline with the crystalline species identified as copper nitrate hydroxide, zinc hydroxide chloride hydrate, and zinc hydroxide nitrate hydrate. Annealing of the aerogel materials at a relatively low temperature (400°C) resulted in a complete phase transition of the material to give highly crystalline ZnO-CuO aerogels; the aerogels consisted of networked nanoparticles in the ~25–550 nm size range with an average crystallite size of ~3 nm and average crystallinity of 98%. ZnO-CuO aerogels are of particular interest due to their particular catalytic and sensing properties. This work emphasizes the versatility of this sol-gel route in synthesizing aerogels; this method offers a possible route for the fabrication of aerogels of different metal oxides and their composites.

Preparation and Characterization of Electrosprayed Nanoparticles containing Ethyl Maltol Flavor

2021 ◽  
Vol 1042 ◽  
pp. 131-136
Author(s):  
Megdi Eltayeb
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Stearic Acid ◽  
Size Distribution ◽  
Entrapment Efficiency ◽  
Narrow Size Distribution ◽  
Transmission Electron

In this study, electrospraying is used to prepare electrosprayed multicomponent nanoparticles of ethylcellulose and stearic acid entrapping ethyl maltol. Electrospraying nanoparticles produced were ≤100 nm diameter and narrow size distribution (polydispersity index 0.26) is achieved. The ethyl maltol entrapment efficiency and yield were approximately 88% and 76%, respectively. The presence of ethyl maltol flavor within the polymeric electrosprayed nanoparticles was shown by Fourier transform infrared spectroscopy. The morphology of the electrosprayed multicomponent nanoparticles generated was studied by transmission electron microscopy.

Amphiphilic architectures based on fullerene and calixarene platforms: From buckysomes to shape-persistent micelles

2008 ◽  
Vol 80 (3) ◽  
pp. 571-587 ◽  
Author(s):  
Andreas Hirsch
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Transfer ◽  
Size Distribution ◽  
Photoinduced Electron Transfer ◽  
Building Blocks ◽  
Water Soluble ◽  
Narrow Size Distribution ◽  
Transmission Electron ◽  
Supramolecular Aggregation

The supramolecular aggregation properties of new prototypes of artificial amphiphiles consisting of fullerene or calixarene building blocks serving as platforms for the connection of hydrophobic and dendritic hydrophilic groups are reported. Very water-soluble monoadducts of C60 carrying a defined number of negative charges at a given pH were hybridized with cationic porphyrins including cyctochrome C and investigated with respect to photoinduced electron transfer. Fullerene adducts with dendritic deprotected sugar addends self-assemble to supramolecular sugar balls in water with a narrow size distribution of the micelles of around 4 nm. Various examples of cone- or T-shaped amphiphiles involving calixarene and fullerene cores self-organize to the first examples of shape-persistent micelles whose supramolecular arrangement in water has been determined with unprecedented precision based on the analysis of cryo-transmission electron microscopy (TEM) investigations.

scholarly journals Thermoluminescence (TL) response of silica nanoparticles subjected to 50 Gy gamma irradiation.

2017 ◽  
Vol 13 (3) ◽  
Author(s):  
Nik Noor Aien Mohamed Abdul Ghani ◽  
Mohammad Alam Saeed ◽  
Izyan Hazwani Hashim
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silica Nanoparticles ◽  
Gamma Rays ◽  
Sol Gel ◽  
Ammonia Solution ◽  
Deionized Water ◽  
Pure Silica ◽  
Transmission Electron ◽  
Size And Morphology

Thermoluminescence (TL) response of silica nanoparticles synthesized by the sol-gel method is presented here. Transmission electron microscopy (TEM) was used to find out the size and morphology of the pure silica nanoparticles. By using an appropriate amount of tetraethylorthosilicate, ethanol, deionized water and ammonia solution, silica samples were synthesized. To determine the best TL response of silica, samples were irradiated with 50Gy gamma rays. The effect of size dependency towards TL yield indicates that decreasing the particles’ size of silica, increases the TL yield.

Synthesis and Characterization of Silica Nanoparticles

2007 ◽  
Vol 121-123 ◽  
pp. 49-52 ◽  
Author(s):  
R. Aghababazadeh ◽  
S. Tabatabae ◽  
Ali Shokuhfar ◽  
A.R. Mirhabibi
Keyword(s):  
Electron Microscopy ◽  
Silica Nanoparticles ◽  
Silica Particles ◽  
Alcoholic Solution ◽  
Chemical System ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Monodisperse Colloidal Silica

Currently there are several models discussed to describe the formation of monodispersed silica particles. Monodisperse colloidal silica was prepared from tetraethoxysilane in mixture of ammonia, water and ethanol. Chemical system reaction permits the controlled growth of silica nanoparticles and subsequent condition of silicic acid in alcoholic solution. The molar ratio of NH4OH, C2H5OH and H2O has a significant effect on particle size and specific surface area of silica particles. The nature of particles was evaluated using X-ray diffraction, energy dispersive spectroscopy (EDS) and BET. The morphology of particles were determined by scanning electron microscopy (SEM) and transmission electron microscopy(TEM).

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