Synthesis Of SiO Research Articles

Temperature‐Optimized Synthesis of SiO2‐Reinforced N‐(Alkyl)Acrylamide‐Based Semi‐IPN Hybrid Gels Functionalized with Methacrylic Acid Units

Front Cover: In article number 2300006, Nermin Orakdogen and co-workers deal with temperature-optimized synthesis of N-(alkyl)acrylamide-based semi-interpenetrating polymer network reinforced with silica nanoparticles and functionalized with methacrylic acid units by varying the polymerization temperature. The gelation is performed at different temperatures to evaluate the formation mechanism. The mechanical properties, swelling properties and susceptibility to stimuli show a wide dependence on the polymerization temperature.

Temperature‐Optimized Synthesis of SiO2‐Reinforced N‐(Alkyl)Acrylamide‐Based Semi‐IPN Hybrid Gels Functionalized with Methacrylic Acid Units

AbstractIn order to obtain a pH and temperature sensitive hybrids with a controlled structure, synthesis of N‐(alkyl)acrylamide‐based semi‐interpenetrating polymer network (semi‐IPN) reinforced with silica (SiO2) nanoparticles and functionalized with methacrylic acid units is carried out by optimizing the polymerization temperature. The study aims to understand the effect of polymerization temperature on the physical properties of semi‐IPN hybrids. Changing preparation temperature between −30 and 23 °C leads to significant differences in physico‐mechanical results, swelling tendency and adsorption ability, while silica nanoparticles strengthen hybrid walls, preventing their collapse during deswelling and providing rapid response. The hybrids prepared at higher temperatures are found to swell more and faster in water, while the lowest swelling is observed those prepared at 5 °C. The incorporation of SiO2 particles into copolymer structure via physical crosslinking with network chains enhances the elasticity. The effect of polymerization temperature on adsorption is investigated using methylene blue as a model dye. Increasing polymerization temperature increases the adsorption rate and shortens time to reach the equilibrium point, and adsorption efficiency increases when polymerization temperature is lowered. The results show that semi‐IPN hybrids loaded with silica nanoparticles can be used as alternative and potential adsorbents in the treatment of industrial wastes.

Synthesis of SiO2@MnCo2O4 core–shell nanorattles using layered double hydroxide precursors and studies on their peroxidase-like activity

The current work demonstrates a simple soft chemical approach to synthesize SiO2@MnCo2O4 core–shell nanorattles using SiO2@MnCo-LDH (layered double hydroxide) precursors.

Synthesis of SiO2@Ag for light absorption and the fabrication of highly color-saturated amorphous photonic crystals

A novel APC structural color film with excellent color visibility and color saturation is fabricated through the layer-by-layer self-assembly of SiO2@Ag and SiO2 microspheres.

<i>In Situ</i> Synthesis of SiO<sub>2</sub> Nanoparticles by Sol-Gel Method on Cotton Fabrics and Investigation of their Physical and Chemical Properties

In this paper, the sol-gel method was used for in-situ synthesis of SiO2nanoparticles (NPs) on cotton fabrics with tetraethyl orthosilicate (TEOS) in the presence of acid and alkaline indicators. The samples were characterized using by(X-ray diffraction)XRD,(scanning electron Microscopy)SEM,(Inductively coupled plasma)ICP, water drop test and also the flame retardant properties were studied by char yield. The SEM images showed that the nanoparticles are spherical in shape and the acidity or alkalinity of the medium has an effect on the formation of particles. The XRD patterns showed the typical diffraction of amorphous SiO2(Si-O short-order structure), also ICP analysis showed that by washing the fabrics, the nanoparticles are still present on the fabric, and this indicated the stability of the washing of the fabrics impregnated with the nanoparticles. By in-situ synthesis of SiO2nanoparticles, the flame retardant properties have been improved significantly and the amount of residual char was increased and samples were observed to be hydrophilic.

Corrigendum: Synthesis of SiO 2 @PAA microspheres and their application for controlling diisooctyl terephthalate migration from flexible PVC materials

Corrigendum: Synthesis of SiO ₂ @PAA microspheres and their application for controlling diisooctyl terephthalate migration from flexible PVC materials

Novel synthesis of SiO /C composite as high-capacity lithium-ion battery anode from silica-carbon binary xerogel

Abstract Micro/nanostructured SiOx/C composite was firstly synthesized by carbothermal reduction of silica-carbon binary xerogel. The homogeneous dispersion feature of the two components in binary xerogel contributes to effectively carbothermally reduce the O/Si atomic ratio, enhancing the electrochemical activity of the SiOx component. The micron-sized SiOx/C spheres are composed of many near-spherical nanoparticles. The synthesized SiOx/C exhibits a stable and high reversible capacity of 830 mA·h·g−1 for 100 cycles, and excellent rate-capability. The homogeneous dispersion structure of phases, the micro/nanostructure and the high electrochemical activity of SiOx component combinedly contribute the excellent electrochemical performance.

The Synthesis of SiO2@AuAg@CeO2 Sandwich Structures with Enhanced Catalytic Performance Towards CO Oxidation

AbstractNovel sandwich structure SiO2@AuAg@CeO2 nanospheres (SACs), as low‐temperature CO oxidation catalysts, were designed and prepared in this work. The SACs include SiO2 nanosphere support, embedded bimetallic AuAg nanoparticles, and CeO2 shell. The transmission electron microscope (TEM), elemental mapping images, and ultraviolet‐visible (UV‐vis) spectroscopy indicated the successful fabrication of the SACs sandwich structure. The catalytic performance of SACs varies with the AuAg composition and achieves the best catalytic activity when Au/Ag atomic ratio is 2:1. The strong synergistic effect of AuAg alloy remarkably promotes the CO oxidation through facilitating the adsorption of CO and O2 on the AuAg nanoparticles. The CeO2 non‐compact shell not only provides effective protection for AuAg nanoparticles from aggregation but also gives CO full access to the catalysts. With unique sandwich structure and specific chemical composition, the SiO2@Au2Ag1@CeO2 nanospheres with CeO2 shell thickness of 5 nm present excellent low‐temperature catalytic activity and high‐temperature thermal stability.

Synthesis of SiO 2 @PAA microspheres and their application for controlling diisooctyl terephthalate migration from flexible PVC materials

The preparation of silicon dioxide (SiO2)@poly(acrylic acid) (PAA) microsphere was reported. The modified microspheres can be well dispersed in polyvinyl chloride (PVC) matrix. The structure of SiO2@PAA microspheres can be well-controlled and its mixtures with chlorinated polyethylene (CPE) for controlling diisooctyl terephthalate (DOTP) migration from PVC matrix. The results showed that the migration of DOTP was decreased with increasing content of SiO2@PAA microspheres, and the use of CPE together with SiO2@PAA microspheres has a synergistic effect on the reduction of DOTP migration. Moreover, CPE can enhance the interface combination between SiO2@PAA microsphere and PVC, and good dispersibility was observed in PVC/CPE/SiO2@PAA composites.

Dissolution-regrowth synthesis of SiO 2 nanoplates and embedment into two carbon shells for enhanced lithium-ion storage

Abstract In this work, SiO 2 nanoplates with opened macroporous structure on carbon layer (C-mSiO 2 ) have been obtained by dissolving and subsequent regrowing the outer solid SiO 2 layer of the aerosol-based C-SiO 2 double-shell hollow spheres. Subsequently, triple-shell C-mSiO 2 -C hollow spheres were successfully prepared after coating the C-mSiO 2 templates by the carbon layer from the carbonization of sucrose. When being applied as the anode material for lithium-ion batteries, the C-mSiO 2 -C triple-shell hollow spheres deliver a high capacity of 501 mA·h·g − 1 after 100 cycles at 500 mA·g − 1 (based on the total mass of silica and the two carbon shells), which is higher than those of C-mSiO 2 (391 mA·h·g − 1 ) spheres with an outer porous SiO 2 layer, C-SiO 2 -C (370 mA·h·g − 1 ) hollow spheres with a middle solid SiO 2 layer, and C-SiO 2 (319.8 mA·h·g − 1 ) spheres with an outer solid SiO 2 layer. In addition, the battery still delivers a high capacity of 403 mA·h·g − 1 at a current density of 1000 mA·g − 1 after 400 cycles. The good electrochemical performance can be attributed to the high surface area (246.7 m 2 ·g − 1 ) and pore volume (0.441 cm 3 ·g − 1 ) of the anode materials, as well as the unique structure of the outer and inner carbon layer which not only enhances electrical conductivity, structural stability, but buffers volume change of the intermediate SiO 2 layer during repeated charge–discharge processes. Furthermore, the SiO 2 nanoplates with opened macroporous structure facilitate the electrolyte transport and electrochemical reaction.

一步水热法合成SiO<sub>2</sub>纳米棒

一步水热法合成SiO<sub>2</sub>纳米棒

Facile Synthesis of SiO2–Ni Raspberry Composites by Electroless Plating and Polyelectrolyte Adsorption

Facile Synthesis of SiO₂–Ni Raspberry Composites by Electroless Plating and Polyelectrolyte Adsorption

Synthesis of SiO2coated zero-valent iron/palladium bimetallic nanoparticles and their application in a nano-biological combined system for 2,2′,4,4′-tetrabromodiphenyl ether degradation

Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants and the degradation of PBDEs is still a significant challenge owing to their extreme persistence and toxicity.

Synthesis of SiO2 nanopowders containing quartz and cristobalite phases from silica sands

Abstract In this study, extraction and synthesis of SiO2 nanoparticles from silica sands have been conducted by means of two different methods, i.e. dry method (method 1) and hydrothermal process (method 2). The basic difference between the two methods is in the extraction step. The two methods were compared in terms of being more efficient, economical, and superior in obtaining SiO2 nanoparticles. The SiO2 nanoparticles were characterized in terms of phase purity, crystallinity, Si-O functional bonding as well as particles size and morphology. The most interesting fact in this study was the formation of both quartz and cristobalite phases within all prepared SiO2 nanoparticles.

Synthesis of SiO2 and CaO rich calcium silicate systems via sol‐gel process: Bioactivity, biocompatibility, and drug delivery tests

Silica and calcium silicate amorphous materials, mixed with sodium ampicillin, a broad-spectrum antibiotic, have been synthesized by sol-gel method. The amorphous nature of the gels was ascertained by X-ray diffraction analysis. The bioactivity of the synthesized materials has been put into evidence by the appearance of a crystal of hydroxyapatite on the surface of the samples soaked in a fluid simulating the composition of the human blood plasma, as detected through FTIR measurements and SEM micrographs. The present work refers to a series of in-vitro biocompatibility tests, which has been performed on silicate and CaO rich calcium silicate gel-glasses, to study the cell behavior when seeded on 1 cm(2) material fragments, introduced into an in-vitro culture system. 3T3 cell lines have been used and the viability has been evaluated by WST-8 test. The composition of the adopted glasses can be expressed by the following general formula: x CaO• (1 - x) SiO2 with x = 0.00; 0.30; 0.40; 0.50; 0.60. Subsequently, release kinetics in a simulate body fluid (SBF) has been investigated. The amount of sodium ampicillin released has been detected by UV-Vis spectroscopy. The release kinetics has appeared to occur in more than one stage. All data have shown that those materials could be used as drug delivery bioactive systems.

Synthesis of SiO2 system via sol–gel process: Biocompatibility tests with a fibroblast strain and release kinetics

SiO2 glass has been synthesized via sol-gel process and enriched with 5 wt % sodium ampicillin. To verify the biocompatibility of the obtained biomaterial, fibroblasts have been grown on a glass surface and were tested for viability after 24 h. The results of the Water-Soluble Tetrazolium (WST)-8 analysis suggest that SiO2 glass has an adequate biocompatibility. The amorphous nature of the gels has been ascertained by X-ray diffraction analysis. Release kinetics have been subsequently investigated in a simulated body fluid. The amount of sodium ampicillin released has been detected by ultraviolet-visible spectroscopy. The release kinetics seems to occur in more than one stage. High-performance liquid chromatography analysis has also been carried out to ensure the integrity of ampicillin after the synthesis treatment.

Synthesis of SiO 2 covered SiC nanowires with milled Si,C nanopowders

SiO 2 covered β-SiC nanowires were directly synthesized with a novel method, annealing the milled Si,C nanopowders at 900–1100 °C on Si wafer or Al 2O 3 substrate, and there is no any metal catalysts used. The diameters of the nanowires are range of 20 to 50 nm, and the lengths of the nanowires are up to several hundreds of microns. There is a uniform SiO 2 amorphous layer on the surface of SiC nanowires. The axial direction of SiC nanowires is < 111>, and there are stacking faults and twin lamellae in the SiC nanowires. The synthetic mechanism of SiC nanowires includes two solid–solid reactions and one gas–solid reaction between SiO, Si, C and CO.

Synthesis of SiO2/PS composite particles via emulsion polymerization

AbstractSiO2 particles prepared by Stöber method were modified using 1,3,5,7‐tetravinyl‐1,3,5,7‐tetramethylcyclotetrasiloxane (Vi‐D4), and SiO2/polystyrene (PS) composite particles with core‐shell structure were synthesized adopting mulsion polymerization of PS in a water–ethanol medium. The products were characterized by infrared spectra, X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Zetasizer analyzer. The average diameter of SiO2 particles prepared by Stöber method was about 80 nm, the SiO2 particles were modified using the molar ratio of Vi‐D4 and SiO2 particles 1 : 10 (the dosage of Vi‐D4 benever too much), and the size of modified silica particles was about 90 nm. The infrared spectra indicated that the Vi‐D4 had bonded to the silanol groups on surface of SiO2 particles, and XPS indicated the grafting efficiency of Vi‐D4 on surface of SiO2 particles had reached 90%. The infrared spectra indicated the PS had been incorporated with SiO2 particles, and TEM indicated the composite particles have obvious core‐shell structure. The suitable size of SiO2 particles should be lower than 200 nm, and the optimum volume ratio of ethanol and water should be 1 : 9 or 1 : 4. A kind of monodisperse SiO2/PS composite particles having function of self‐assembling was successfully and effectively synthesized. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Synthesis of well-defined structurally silica–nonlinear polymer core–shell nanoparticles via the surface-initiated atom transfer radical polymerization

We report on the synthesis of the well-defined structurally silica–nonlinear polymer core–shell nanoparticles via the surface-initiated atom transfer radical polymerization. At first, 3-(2-bromoisobutyramido)propyl(triethoxy)-silane (the ATRP initiator) was prepared by the reaction of 3-aminopropyltriethoxysilane with 2-bromoisobutyryl bromide. The ATRP initiator was covalently attached onto the nanosilica surface. The subsequent ATRP of HEMA from the initiator-attached SiO 2 surface was carried out in order to afforded functional nanoparticles bearing a hydroxyl moiety at the chain end, SiO 2-g-PHEMA-Br. The esterification reaction of pendent hydroxyl moieties of PHEMA segment with 2-bromoisobutyryl bromide afforded the SiO 2-based multifunctional initiator, SiO 2-g-PHEMA(-Br)-Br, bearing one bromine moiety on each monomer repeating unit within the PHEMA segment. Finally, the synthesis of SiO 2-g-PHEMA(-g-PSt)-b-PSt was accomplished by the ATRP of St monomer using SiO 2-g-PHEMA(-Br)-Br as multifunctional initiator. These organic/inorganic hybrid materials have been extensively characterized by FT-IR, XPS, TG, and TEM.

Spatially confined synthesis of SiO_x nano-rod with size-controlled Si quantum dots in nano-porous anodic aluminum oxide membrane

By depositing Si-rich SiOx nano-rod in nano-porous anodic aluminum oxide (AAO) membrane using PECVD, the spatially confined synthesis of Si quantum-dots (Si-QDs) with ultra-bright photoluminescence spectra are demonstrated after low-temperature annealing. Spatially confined SiOx nano-rod in nano-porous AAO membrane greatly increases the density of nucleated positions for Si-QD precursors, which essentially impedes the route of thermally diffused Si atoms and confines the degree of atomic self-aggregation. The diffusion controlled growth mechanism is employed to determine the activation energy of 6.284 kJ mole(-1) and diffusion length of 2.84 nm for SiO1.5 nano-rod in nano-porous AAO membrane. HRTEM results verify that the reduced geometric dimension of the SiOx host matrix effectively constrain the buried Si-QD size at even lower annealing temperature. The spatially confined synthesis of Si-QD essentially contributes the intense PL with its spectral linewidth shrinking from 210 to 140 nm and its peak intensity enhancing by two orders of magnitude, corresponding to the reduction on both the average Si-QD size and its standard deviation from 2.6 to 2.0 nm and from 25% to 12.5%, respectively. The red-shifted PL wavelength of the Si-QD reveals an inverse exponential trend with increasing temperature of annealing, which is in good agree with the Si-QD size simulation via the atomic diffusion theory.