Preparation Of SiO Research Articles

Preparation of SiO2-polydimethylsiloxane-octadecyltrichlorosilane superhydrophobic coating and its self-healing performance

The self-healing performance of superhydrophobic coatings is an important property to enhance the durability and self-cleaning character, which has been a focus of surface modification in recent years. In this work, a simple method was proposed for preparing the superhydrophobic coatings with self-healing properties on slides using nano-SiO2, octadecyltrichlorosilane, and polydimethylsiloxane. The hydrophobic properties, morphologies, compositions, structures, stability, and self-healing properties were respectively investigated via various characterizations and tests. The results indicated that the self-healing properties of the coatings were induced by the Si-O-Si bonds through X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The best self-healing property and hydrophobicity after healing were obtained when the content of polydimethylsiloxane was 35% (wt.), and the contact angle of water would arrive at 160.98° when the concentration of nano-SiO2 was 3% (wt.). The contact angle of each coating surface remained stable and thermally stable when the temperature was increased from 100 to 300 °C ( Tg), and the coatings remained stable under natural acidic and alkaline environments as well as mechanical shocks. So superhydrophobic coatings with self-healing performance have potential applications for the development of durable surfaces.

Preparation of SiO<sub>2</sub>-decorated Stainless-steel Powders by Hetero-agglomeration Method and Their Application for Laser Additive Manufacturing

Preparation of SiO<sub>2</sub>-decorated Stainless-steel Powders by Hetero-agglomeration Method and Their Application for Laser Additive Manufacturing

Preparation of SiO2-Fluorinated Acrylate Polymer Nanoemulsions (SCFs) and Their Application as Depressurization and Injection Treatment Agents

For water injection development in low-permeability reservoirs, nanoscale SiO2-fluorinated acrylate polymer nanoemulsions (SCFs) with good properties were prepared through core–shell emulsion polymerization. The results show that nano-SiO2 particles are well dispersed, the average particle size of the SCFs is 113 nm, and the synergy among fluoride chain segments is good and effectively improves the utilization of fluorine atoms. SCFs form a low-surface-energy nanoscale hydrophobic film on the rock surface, which changes the original rock surface micro- or nanostructure, resulting in a water contact angle of up to 120° at the core. At 60 °C, the interfacial tension (IFT) between a 1500 mg/L SCF dispersion and white mineral oil is 1.86 mN/m, decreasing by 95.67% relative to the oil–water IFT at room temperature. The core flooding experiment shows that the depressurization rate reaches 29.62% in the 1500 mg/L SCF dispersion. Therefore, SCFs have broad application prospects in processes that eliminate water lock, reduce injection pressure, and increase injection volume.

Mechanical-electromagnetic integration design of Al[formula omitted]/SiO[formula omitted] ceramic cellular materials fabricated by digital light processing

Mechanical-electromagnetic integrated design has great potential in the development of electromagnetic shielding equipment for military use. In this study, Al2O3/SiO 2 ceramics with triply periodic minimal surfaces (TPMSs) were fabricated using digital light processing (DLP) technology. The preparation of SiO 2 and Al2O3 powders is vital for DLP because minimal aggregates or sedimentation in the ceramic paste is required. Debinding and sintering programs were developed to prevent defects in the designed microstructure. The interfacial characterization demonstrated that the surfaces of the sintered ceramics were compact and smooth. The compression strength of the TPMS ceramic with a volume fraction of 50% was 24 MPa, which is relatively good among additively manufactured cellular ceramics. The TPMS structures also exhibited significant electromagnetic interference (EMI) shielding effectiveness in the X-band (2 to 18 GHz), and the shielding performance was adequate to meet the demands of electromagnetic shielding materials. Additive manufacturing of Al2O3/SiO2 ceramic with TPMS architectures was successfully achieved by considering the mechanical-electromagnetic integration.

Preparation of SiO2 resin coating with superhydrophobic wettability and anti-icing behavior analysis.

Among different types of anti-icing coatings, superhydrophobic surfaces have attracted extensive attention due to their excellent water repellency and low thermal conductivity. We report facile spraying time tuning to optimize the superhydrophobic (SHP) surface coating fabrication by a one-step spraying method of mixing SiO2 nanoparticles with epoxy resin (EP), polyamide resin (PAI), and HFTMS. The wettability performance was optimized by adjusting spraying time from 0 s to 25 s to control surface morphology by adjusting surface morphology and line roughness. With spraying time of 20 s, SiO2 molecular clusters on the superhydrophobic surface showed a maximum water contact angle (WCA) of 160.4° ± 1.3° and a sliding angle (SA) of 4.1° ± 1.0°. What's more, the effect of the coatings' icing behavior were studied by icing heat conduction; SHP-20 delayed the icing time for 410 s at -15 °C, and the icing performance of SHP-20 also declined with the decrease of temperature to -9 °C, -12 °C, -15 °C, and -18 °C. The WCA of SHP-20 can remain above 140.9° ± 1.8° after 40 abrasive 1000# sandpaper wear cycles. The results also provide a basis for the preparation of SHP and anti-icing characteristics.

Surfactants assisted SiO2-Cu@Fe2O3 nanofibers: Ultra efficient photocatalyst for photodegradation of organic compounds and transesterification of waste edible oil to biodiesel

The researchers are trying to synthesize such materials which have desirable stability, high efficiency and cost effective. In the present work, SiO 2 -Cu@Fe 2 O 3 nanofibers were synthesized by a novel protocol in which tween-80 and cetyltrimethylammonium bromide was used as a surfactant. The photodegradation of dyes and transesterification of waste edible oil to biodiesel had been investigated. Copper nanoparticles were relatively well dispersed over the surfaces of silica and iron oxide nanofibers with the diameter of 20 nm and Fe 2 O 3 and SiO 2 composite mesopores with a high specific surface area (116 m 2 /g). Photocatalytic degradation of Methylene blue (MB) and rhodamine B (Rhod B) dyes has been tested against As-synthesized SiO 2 -Cu@Fe 2 O 3 nanostructures. At optimum processing conditions SiO 2 -Cu@Fe 2 O 3 displayed a far higher effectiveness of reaction and dyes degradation than many others. A comparative kinetic study of the reduction of dyes (MB and Rhod B) in the presence and absence of nanocatalyst shows the efficiency of synthesized SiO 2 -Cu@Fe 2 O 3 . Furthermore, the reusability of the as-prepared composite was measured and there is no considerable catalytic activity loss even after 5 cycles. The efficiency of SiO 2 -Cu@Fe 2 O 3 was tested both in light and dark. The visible light efficiency of SiO 2 -Cu@Fe 2 O 3 nanofibers against the said dyes were several time higher than in dark. The degradation patterns at a temperature range of 30 °C were so well equipped with a 1st order kinetic framework and proposed a dyes reaction mechanism. The synthesized nanofibers were also applied as a catalyst against transesterification of waste edible oil to biodiesel. The results indicated that 98% biodiesel production was obtained in a 7 h reaction time, and 70 °C reaction temperature. On the basis of the above high efficiency further research is required on the said nanofibers to investigate their hidden applications. • Preparation of SiO 2 -Cu@Fe 2 O 3 nanofibers by new method. • Photocatalytic​ degradation of methylene blue and Rhodamine B. • Catalytic conversion of waste edible oil to biodiesel. • Investigated different factors effecting the catalytic activity.

Study on the Preparation of SiO 2 / NR Composite

纳米 SiO 2 ；天然橡胶；复合材料；耐老化性能

Determination of modulus of elasticity and bending strength of wood material impregnated with nanoparticle silicon dioxide (SiO2)

The purpose of this study is to determine the effects of the nano-particulate silicon dioxide (SiO2) material on the bending strength and modulus of elasticity in bending of some wood species. Oriental beech (Fagus orientalis L.) and sessile oak (Quercus petrea L.) woods species which are commonly used in the furniture industry were used in this study. Impregnation was carried out with the preparation of SiO2 at concentrations of 1% and 3% according to ASTM-D 1413-76 (1976) standards. According to the results, while solution concentration was increasing in both wood species, total retention (kg/m3) and percentage retention (%) values increased; air dry density (12%), bending strength and modulus of elasticity in bending decreased. The maximum mean values of bending strength and modulus of elasticity was in control samples of oriental beech and the minimum were in sessile oak wood with 3% concentration. These results can be related to the fact that the higher density of oriental beech wood (0.630-0.685 g/cm³). In both species of wood, impregnation with SiO2 resulted loss of about 3-5% in bending strength and 0.6-9% in modulus of elasticity.

A simple way to control the filling degree of the SiO2/Si template pores with nickel

The paper demonstrates a simple way to control the filling degree of the pores of a silicon oxide template on silicon substrate with nickel. SiO2/Si template was formed using the swift heavy ion tracks technology, which includes irradiation with high energy ions and chemical transformation of the obtained latent tracks into the pores. The preparation of SiO2(Ni)/Si nanostructures with different filling degree of pores in SiO2 with nickel was performed using the electrodeposition method by changing the duration of the process. A study and analysis of the morphology of SiO2(Ni)/Si nanostructures using scanning electron and atomic force microscopy was carried out to determine the nature of pore filling by metal

A device for measuring the scattering indicatrix of the nanomaterial synthesis process

An installation diagram for the study of nanomaterials using scattering indicatrices has been presented. It has been shown that the suggested procedure allows the online investigation and control of the synthesis of nanomaterials, as exemplified by the preparation of SiO2 by the Stober method and chemical bath deposition of the lead sulfide PbS layer.

Preparation of SiO2/PS superhydrophobic fibers with bionic controllable micro–nano structure via centrifugal spinning

We present a novel and simple centrifugal spinning technology that extrudes fibers from polymer solutions by using a high-speed rotary, perforated spinneret. And large amount of superhydrophobic micro/nano fibers can be prepared by using it.

Methyl tert-butyl ether as a new solvent for the preparation of SiO2–TiO2 binary aerogels

SiO2–TiO2 binary aerogels have been synthesized for the first time using methyl tert-butyl ether as supercritical fluid. It has been shown that the aerogels prepared in methyl tert-butyl ether and isopropanol contain nanocrystalline anatase and that amorphous SiO2–TiO2 aerogels with a homogeneous distribution of their components can be obtained in CO2. A considerable contribution to the large specific surface area of the aerogels is made by micropores, especially when supercritical drying is carried out in CO2 and isopropanol.

Preparation of SiO2 and SiO2–Al2O3 catalysts by gel skeletal reinforcement using hexamethyldisiloxane (HMDS) and acetic anhydride and aluminum tri-sec-butoxide (ASB) systems and elucidation of their catalytic cracking properties as matrices

Novel amorphous silica with extremely large mesopores were prepared using the gel skeletal reinforcement method with hexamethyldisiloxane (HMDS) and acetic anhydride (AA) system as reinforcing reagents. Pore volume and pore diameter increased with increasing the amounts of HMDS added. When three times higher moles of HMDS than that of silica source TEOS were used, pore volume and pore diameter of prepared amorphous silicas reached larger than 5 cm3/g and 44 nm, respectively, even after calcination at 600 °C for 3 h. The mixed catalysts prepared with the reinforced silica, β zeolite and alumina-sol binder showed much higher conversions of n-dodecane than respective single zeolite even though these catalysts included only 26 wt% of zeolite. The activity tended to increase with increasing pore size and pore volume of the reinforced silica. When aluminum tri-sec-butoxide (ASB) was used as a gel reinforcing reagent, alumina was introduced on the silica surface. In catalytic cracking of n-dodecane the mixed catalysts using ASB reinforced silica showed higher conversion than the catalysts using HMDS, indicating that silicas reinforced by ASB formed silica–alumina in the external surface which played a role of additional acid sites.

Preparation of SiO2–GO hybrid nanoparticles and the thermal properties of methylphenylsilicone resins/SiO2–GO nanocomposites

Silica–graphene oxide (SiO2–GO) hybrid nanoparticles have been prepared by the hydrolysis of tetraethoxysilane (TEOS) in the presence of GO sheets. The results indicated that silica nanoparticles were densely and uniformly grafted onto the GO surface by covalent linkage. The thermal stability of SiO2–GO has been improved greatly according to thermogravimetric analysis (TGA). Methylphenylsilicone resins (MPSR) with various proportions of SiO2–GO were synthesized by solution blending method. The incorporation of SiO2–GO was beneficial to improve the thermal stability and oxidation resistance of composites. The 5% weight loss temperature of the composites at 1wt% SiO2–GO loading was detected 34.8°C higher than that of pure MPSR. And the Tg of composites was increased by 10.4°C. Additionally, the short-term and long-term stability of composites were improved greatly by adding SiO2–GO. These enhancements can be attributed to better dispersion of SiO2–GO in MPSR and improved interfacial adhesion between MPSR and SiO2–GO.

Dispersion of TiO2 particles and preparation of SiO2 coating layers on the surfaces of TiO2

Fine TiO2 has been widely used as a white pigment, but the aggregation of TiO2 particles related to the high specific surface area makes it a challenge to modify its surface. In this paper, NaOH and Na2SiO3 were adopted as regulators for the pH of TiO2 aqueous dispersion. It was discovered that when the pH is 12, the TiO2 particles have the maximum zeta potential and the repulsive force between two TiO2 particles is also at the maximum, which is favourable for the dispersion of TiO2. In terms of the modifying the surface, it was proved that a continuous and compact film of hydrous silica on the surface of TiO2 particles is produced by coprecipitation of Na2SiO3 and H2SO4 when the TiO2 particles are adequately dispersed by ultrasound at pH 12. Furthermore, it was found that the morphology of SiO2 is different when Na2SiO3 and H2SO4 solutions are added in different ways.

Preparation of SiO2@ Au nanorod array as novel surface enhanced Raman substrate for trace pollutants detection**Project supported by the National Basic Research Program of China (Grant No. 2013CB934301), the National Natural Science Foundation of China (Grant No. 50931002), the Research Project of Chinese Ministry of Education (Grant No. 113007A), and the Initiative Scientific Research Program of Tsinghua University, China

An effective surface enhanced Raman scattering (SERS) substrate is designed and fabricated by synthesis of SiO2 nanorods array via glancing angle deposition, followed by coating Au nanoparticles onto SiO2 surface in order to create numerous “hot spots”. The detecting sensitivity of such substrate could be optimized by simply adjusting the deposition time of Au. Thus, it can be used for detection of Rhodamine 6G at concentration as low as 10−9 M. Furthermore, our SERS substrate is applied to detect 5 μg/g polychlorinated biphenyls in soil sample, which proves its potential for trace environmental pollutants detection.

Preparation of SiO2 aerogel from rice husk ash

Silica was leached from rice husk ash as sodium silicate by NaOH treatment.

Preparation of SiO2/dye luminescent nanoparticles and their application in light-converting films

Highly luminescent and photostable dye-h-silica (dye-hybrid-silica) nanoparticles (NPs) were prepared using a base-catalyzed reverse microemulsion method. We obtained dye-h-silica nanoparticles with ∼65 nm radius, a narrow particle size distribution, high fluorescence intensity, and a controlled internal architecture. The luminescence intensity of the dye-h-SiO2 is 2.4 times higher than that of the pure dye in aqueous solution. The incorporation of dye molecules into the silica NPs protects the dye from the surrounding environment, as the silica layer is a good shield against oxygen and moisture, so that the dye-h-silica monoliths (SMs) maintain their initial luminescence after the encapsulation curing process. Green and red light-emitting dye-h-SMs are successfully applied to the preparation of remote trigger LEDs.

Dielectric barrier discharge plasma-mediated synthesis of several oxide nanomaterials and its characterization

This study deals with the preparation of SiO2, CuO and RuO2 nanomaterials and RuO2 based nanocomposites using dielectric barrier discharge (DBD) plasma. On account of an increasing attention toward the preparation of one dimensional nanostructure in recent days, the possibility to tune the morphology of the above materials by using plasma was investigated. The prepared nanomaterials were characterized by using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction spectroscopy and particle size analysis. Spherical, cylindrical and nanorod structures were observed for SiO2, CuO and RuO2, respectively. The morphology and the chemical composition of the RuO2/SiO2 and RuO2/CuO nanocomposites were analyzed using high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. It was noted that interaction of plasma species with each material differs from one another, and thus the materials exhibit different surface morphology. The reason might be the material's physico-chemical properties and in particular, depending on whether they belong to insulator or semiconductor.

Preparation of SiO2 nanoparticles and investigation of its tribological behavior as additive in liquid paraffin

Purpose – The purpose of this work is to study tribological properties of liquid paraffin with SiO2 nanoparticles as an additive, which are made by surface-modification method. Taguchi robust designs for optimization in synthesizing SiO2 nanoparticles by sol-gel method. Design/methodology/approach – The tribological properties of the SiO2 nanoparticles as additive in liquid paraffin are studied by ball-on-ring wear tester to find out optimal concentration, and the mechanism of the reduction of wear and friction will be investigated by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and atomic force microscope (AFM). Findings – Under optimal conditions identified by Taguchi robust designs method, SiO2 nanoparticles with a narrow particle size distribution can be obtained and optimal concentrations of SiO2 nanoparticles as additives in liquid paraffin have better properties than the pure paraffin oil. Originality/value – It is shown in the paper that by reducing friction and AW, the lubricant prepared by the methods described can prolong operating hours of machinery.