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The objective of this study is to synthesize hollow SiO2 nanospheres (HSNs), and to investigate the effect of varying divinylbenzene (DVB) amounts during synthesis on their morphology and pore structure. Additionally, it seeks to characterize the thermal conductivity of the synthesized HSNs and evaluate the impact of their incorporation on the thermal insulation properties of acrylic coatings. Single‐shell HSNs were synthesized using the Stöber method, which involved hydrolysis‐polycondensation of tetraethyl orthosilicate. The double‐shell HSNs were prepared using a stepwise wrapping synthesis method, with single‐shell HSNs as the core matrix and an appropriate amount of crosslinking agent added. The addition of DVB resulted in different morphologies, shell spacings, and specific surface areas for the double‐shell HSNs. The thermal conductivity of the double‐shell HSNs decreased significantly to as low as 0.0252 W·m1·K−1 with an increase in shell spacing. The shell spacing of double‐shell HSNs had doubled, resulting in a reduction of its thermal conductivity by approximately 18%. When the double‐shell HSN content reached 8%, the thermal conductivity decreased by 85% compared to that of the original acrylate coating. These results indicate that double‐shell HSNs can substantially decrease the thermal conductivity of the matrix material for thermal insulation applications. [ABSTRACT FROM AUTHOR]

Extracting microplastics from natural sources is challenging, especially microplastics with sizes smaller than 100 μm. The flotation method is the most common microplastic extraction, but it struggles with fine particles due to the difficulty in collecting floating plastic particles from the liquid during the separation process. This study proposes a new floating media, tetraethyl orthosilicate (TEOS), that could separate microplastics using its hydrophobic-oleophilic properties. Most interestingly, TEOS transformed from a liquid state to a solid state (gel) by hydrolysis and condensation reactions, thus safely capturing the separated microplastic particles after flotation and mitigating particle loss from scooping since its gel acted as a particle holder. The average recovery rates obtained were in the range of 95–100% for polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polytetrafluoroethylene, and aged tyre rubber. The recovery rates were slightly reduced for finer particles (sizes down to 40 μm) at 82–98%. TEOS-based extraction provided a higher recovery rate for non-polar plastics than for polar or hydrophilic plastics. The separated microplastics maintained their characteristics for polymer identification, as proven by spectroscopic and thermal analysis techniques. Therefore, TEOS-based extraction could be a new approach to microplastic extraction, especially for preventing fine particle loss. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries are increasingly required to operate under harsh conditions, particularly at high temperatures above 55 °C. However, existing electrolytes suffer from inadequate thermal stability and significant interphasial side reactions. Moreover, there is a lack of clear guidelines for developing electrolytes that can withstand high temperatures. Here a solvent screening descriptor is introduced based on dual local softness and dielectric constant. The findings indicate that solvents with moderate dielectric constants and low reactivity are ideal candidates for high‐temperature electrolytes. Among the solvents evaluated, tetraethyl orthosilicate (TEOS) is identified as a suitable option and is utilized to formulate a localized high‐concentration electrolyte (TEOS‐based LHCE). Remarkably, the 1‐Ah LiNi0.8Co0.1Mn0.1||graphite pouch cell utilizing this TEOS‐based LHCE demonstrates 95.8% capacity retention after 300 cycles at 60 °C. Interphasial analysis reveals that the TEOS‐based LHCE promotes the formation of thin, uniform LiF‐rich interphases, effectively suppressing interfacial side reactions at elevated temperatures. This screening strategy not only enhances the understanding of electrolyte performance but also paves the way for high‐throughput screening of electrolytes suitable for wide‐temperature lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

Traditional anticorrosion coatings often suffer from reduced effectiveness or even complete failure due to the formation of microcracks. Isophorone diisocyanate (IPDI) can form a polyurea structure without a catalyst in the presence of water, which can protect the underlying metal from corrosion. In this study, an anticorrosion coating with self-healing properties was developed by incorporating microcapsules containing IPDI into the coating formulation. Silica-based self-healing microcapsules were synthesized via interfacial polymerization, using tetraethyl orthosilicate as the precursor and IPDI as the core material. The effects of core-to-wall ratio, reaction temperature, different emulsifiers, and emulsifier ratios on the microcapsule properties were investigated. The results demonstrated that microcapsules prepared using a composite emulsifier system of cetyltrimethylammonium bromide (CTAB) and OP-10 at a 1:1 ratio, with a core-to-wall ratio of 1:1, and a reaction temperature of 75°C, exhibited a smooth surface, spherical shape, and excellent encapsulation efficiency. The maximum core content achieved was 81.2 wt%. An epoxy coating embedded with these self-healing microcapsules was subjected to scratching damage. After applying water to the surface and allowing it to stand for 2 days, the scratches healed, and the steel plate surface remained free from corrosion, indicating excellent self-healing performance. [ABSTRACT FROM AUTHOR]

ABSTRACT Schiff‐base materials are known ligands for the coordination of metal ions and the synthesis of various stable and useful complexes. Therefore, herein, a novel Schiff‐base compound {2,2′‐((1E,11E)‐2,5,8,11‐tetra azadodeca‐1,11‐diene‐1,12‐diyl) bis (4‐bromophenol)} was introduced that formed from condensation of triethylenetetramine (TETA) and 5‐bromo‐2‐hydroxybenzaldehyde (5B2HB). This Schiff‐base ligand was labeled as TADDbBP. Besides, mesoporous MCM‐41 was synthesized using tetraethyl orthosilicate (TEOS), hydrolyzing cetyltrimethylammonium bromide (CTAB) and NaOH solution (2 M), followed by calcination at 550 °C, and further, the silanol sites on the MCM‐41's surface were modified by 3‐chloropropyltriethoxysilane (3Cl‐PTES), which modified MCM‐41 was labeled as 3‐Cl‐Pr@MCM‐41. In the next step, the synthesized TADDbBP (as Schiff‐base ligand) was grafted on 3‐Cl‐Pr@MCM‐41, which was labeled as TADDbBP@MCM‐41, and further, it was coordinated with samarium ions (which was labeled as Sm‐TADDbBP@MCM‐41 nanocatalyst) using Sm (CH3COO)3. This is the first report on the production of Sm‐TADDbBP@MCM‐41 nanocatalyst, this nanocatalyst was characterized by TEM, SEM, EDX, elemental mapping, BET method, ICP, XRD, and TGA techniques. In the final step, the catalytic performance of Sm‐TADDbBP@MCM‐41 nanocatalyst has been checked in the homo‐selective producing of tetrazoles through [2 + 3] cycloaddition of benzonitriles and sodium azide (NaN3) in PEG‐400 as available, nontoxic, green, and safe solvent. This nanocatalyst provides excellent selectivity in the synthesis of tetrazoles. In addition, Sm‐TADDbBP@MCM‐41 nanocatalyst can be separated and recycled for several cycles without significant reactivation or metal leaching. [ABSTRACT FROM AUTHOR]

The resistance of epoxy composite modified with nanocellulose and tetraethoxysilane (TEOS) to decay by white rot (Trametes versicolor) and brown rot (Coniophora puteana) fungi was investigated using EN 113 (1996) as the guideline. The objective of this study was to investigate the effect of TEOS as a cross-linked agent in epoxy/nanocellulose composite, and its resistance against white rot and brown rot fungi. The epoxy resin was mixed with 10 wt% nanocellulose. The other three sets were prepared the same, but with the addition of 1%, 2%, and 3% TEOS for each set. All types of epoxy composites were air dried in a mold at ambient temperature for seven days followed by oven drying at 80 °C for 30 min. The composites were oven dried at 103 °C, sterilized, and exposed to the fungi at 22 °C for 16 weeks. It was found that the use of 1% to 3% TEOS in the composite reduced the percent weight loss following decay by T. versicolor, but not in the case of C. puteana. Overall, all types of the composite in this study were classified as highly durable and durable against the T. versicolor and C. puteana respectively. The surface and structure of all types of composites were still intact after 16 weeks of exposure period. [ABSTRACT FROM AUTHOR]

In this study, to address the defects of sodium alginate (SA), such as its susceptibility to disintegration, silica was coated on the outer layer of sodium alginate hydrogel beads in order to improve its swelling and slow-release properties. Tetraethyl orthosilicate (TEOS) was used as the hydrolyzed precursor, and the solution of silica precursor was prepared by sol-gel reaction under acidic conditions. Then SA–silica hydrogel beads prepared by ionic crosslinking method were immersed into the SiO2 precursor solution to prepare SA–silica hydrogel beads. The chemical structure and morphology of the hydrogel beads were characterized by XRD, FTIR, and SEM, and the results showed that the surface of SA–silica beads was successfully encapsulated with the outer layer of SiO2, and the surface was smooth and dense. The swelling experiments showed that the swelling performance effectively decreased with the increase of TEOS molar concentration, and the maximum swelling ratio of the hydrogel beads decreased from 41.07 to 14.3, and the time to reach the maximum swelling ratio was prolonged from 4 h to 8 h. The sustained-release experiments showed that the SA–silica hydrogel beads possessed a good pH sensitivity, and the time of sustained-release was significantly prolonged in vitro. Hemolysis and cytotoxicity experiments showed that the SA-silica hydrogel beads were biocompatible when the TEOS molar concentration was lower than 0.375 M. The SA–silica-2 hydrogel beads had good biocompatibility, swelling properties, and slow-release properties at the same time. [ABSTRACT FROM AUTHOR]

MCM-41 spheres of 300–400 nm size were synthesized using a modified Stöber method at room temperature. We found that the pH value changed with the hydrolysis of tetraethyl orthosilicate in the process, which was not conducive to the formation of ordered mesoporous structures. Therefore, buffer solutions (NaH2PO4 + NaOH, Glycine + NaOH, KCl + NaOH) were added to the system and the pH was successfully stabilized. MCM-41 particles synthesized using the buffer solution have a more ordered mesoporous structure. Results demonstrate that the BET surface area of MCM-41 improved from 1490 ± 7 to 1672 ± 9 m2/g after adding the buffer solution. The efficacy of this synthetic method may be attributed to the stabilized pH value and enhanced effect of H2NCH2COO ions on the formation of ordered templates. [ABSTRACT FROM AUTHOR]

The controllable α/β ratio of Si 3 N 4 powder was synthesized using tetraethyl orthosilicate (TEOS), glucose, MgCl 2 and YCl 3 ·6H 2 O by sol-gel assisted carbothermal reduction and nitridation (CRN). This study aimed to investigate the impact of various parameters, including a H 2 O/TEOS mol ratio of the sol, a C/Si mol ratio, sintering aids, and the temperature of CRN on the phase transformation of α-Si 3 N 4. The results demonstrated that the H 2 O/TEOS ratio significantly influenced the relative content of α and β phase in Si 3 N 4 by changing the morphological characteristics of SiO 2. When the H 2 O/TEOS ratio was 100, β-Si 3 N 4 powder with an approximate β content over 88 wt% was synthesized at 1500 °C. This remarkable phase transformation was likely facilitated by the eutectic liquid phase consisting of MgSiO 3 /Mg 2 SiO 4. The SEM image revealed rod-like whiskers with a length around 1.4 μm for the β-Si 3 N 4 grains. Due to the presence of liquid phase, the synthesis of spherical-like α-Si 3 N 4 nano-powder with an α-phase content of 91 wt% was achieved at a lower temperature of 1450 °C, with an H 2 O/TEOS ratio of 15 and a C/Si ratio of 4. The size of the particles was about 70 nm due to the reduced reaction temperature. Furthermore, without the addition of any sintering aids or Si 3 N 4 seeds, high purity α-Si 3 N 4 with an α phase content approaching 96 wt% could be synthesized at 1500 °C, using an H 2 O/TEOS ratio of 15 and a C/Si ratio of 4. The resulting α-Si 3 N 4 powder exhibited an extremely regular hexagonal prism shape with a length of approximately 2 μm. [Display omitted] [ABSTRACT FROM AUTHOR]

Metal halide perovskite light‐emitting diodes (PeLEDs) are gaining increasing attention as a promising candidate for the new‐generation display technology. Although tremendous progress has been witnessed in this field, the device performance of blue PeLEDs still lags far behind that of the green and red counterparts. In this work, an effective interfacial engineering is employed to boost the radiative recombination of blue perovskite film by introducing a multifunctional tetraethyl orthosilicate (TEOS) network on the grain‐growth substrate. Benefitting from the strong interaction between the TEOS molecule and perovskite nuclei, the perovskite crystallization dynamics are effectively regulated, contributing to significantly improved emitting film with uniformly distributed halogen and concentrated low‐dimensional domain. Additionally, the TEOS network can distinctly passivate the crystal defects at the buried perovskite interface owing to its adequate electron‐donating sites. Consequently, the target blue PeLEDs featuring a stable emission peak at 488 nm exhibit a champion external quantum efficiency of 17.3%, which is among the highest values to date. The results demonstrate the critical role of the surface molecular characteristics of the grain‐growth substrate in regulating the mixed‐halide blue perovskite crystallization. [ABSTRACT FROM AUTHOR]

Amid the global water crisis, developing innovative solutions for sustainable water purification is crucial. Membrane distillation (MD) has emerged as a pivotal method with significant potential to address these challenges effectively. In this research endeavor, our team focused on creating and optimizing an omniphobic membrane utilizing a combination of Poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP), Tetraethyl orthosilicate (TEOS), and Perfluorodecyltrimethoxysilane (PFDTMS) through the nonsolvent-induced phase separation (NIPS) methodology. The resultant membrane displayed a notable contact angle of 130°, underscoring its remarkable omniphobic properties. Various characterization techniques were used to evaluate the membrane's performance, including liquid entry pressure (LEP), porosity analysis, thickness determination, pore size quantification, and scanning electron microscopy (SEM). SEM images revealed enhanced surface roughness, which is critical for efficiency. Additionally, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDS) provided insights into the membrane's crystalline structure and chemical composition. [ABSTRACT FROM AUTHOR]

This article describes the synthesis of a hydrophobic protective coating for concrete based on a silane derivative of fatty acids. The coating was obtained through a thiol-ene click addition reaction using methyl oleate and 3-mercaptopropyltrimethoxysilane in the presence of the photoinitiator 2,2-dimethoxy-2-phenylacetophenone (DMPA). This reaction proved to be more efficient compared with other tested (photo)initiators, considering the double bond conversion of oleate. The coating was applied to concrete using two methods: immersion and brushing. Both methods exhibited similar consumption of methyl oleate-based silane (UVMeS) at approximately 20 g/m2. The hydrophobic properties of the coatings were evaluated based on the contact angle, which for the modified surfaces was above 93°, indicating their hydrophobic nature. The penetration depth of the silane solution into the concrete was also studied; it was 5–7 mm for the immersion method and 3–5 mm for the brushing method. The addition of tetraethoxysilane (TEOS) to the silane solution slightly improved the barrier properties of the coating. [ABSTRACT FROM AUTHOR]

Dental resin composites are widely used in clinical settings but often face longevity issues due to the development and accumulation of microcracks, which eventually lead to larger cracks and restoration failure. The incorporation of microcapsules into these resins has been explored to introduce self-healing capability, potentially extending the lifespan of the restorations. This study aims to enhance the performance of self-healing dental resins by optimizing the microcapsules–resin matrix physicochemical interactions. Poly(urea–formaldehyde) (PUF) microcapsules were reinforced with melamine and subsequently subjected to surface functionalization with 3-aminopropyltriethoxysilane (APTES) and (3-mercaptopropyl)trimethoxysilane (MPTMS). Additionally, microcapsules were functionalized with a bilayer approach, incorporating tetraethyl orthosilicate (TEOS) with either APTES or MPTMS. X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) confirmed an increased Si:C ratio from 0.006 to 0.165. The functionalization process did not adversely affect the structure of the microcapsules or their healing agent volume. Compared to PUF controls, the functionalized microcapsules demonstrated enhanced healing efficiency, with TEOS/MPTMS-functionalized microcapsules showing the highest performance, showing a toughness recovery of up to 35%. This work introduces a novel approach to functionalization of microcapsules by employing advanced silanizing agents such as APTES and MPTMS, and pioneering bilayer functionalization protocols through their combination with TEOS. [ABSTRACT FROM AUTHOR]

• Propose a novel flexible-rigid hybridizing strategy to address the cracking issues in siloxane-based consolidants. • Synthesize a flexible-rigid hybrid siloxane material through self-catalyzed copolymerization. • Put forward one consolidation mechanism based on three-dimensional continuous network. • Successfully strengthen the weathered stone of Tianlong Mountain Grottoes. Siloxane oligomers produced through the hydrolysis of tri-alkoxysilanes or tetra-alkoxysilanes have been widely used as consolidants for stone heritage. However, the resulting xerogels tend to crack due to the volume shrinkage after curing. In this study, a novel flexible-rigid hybrid siloxane oligomer material is designed by the self-catalyzed copolymerization of di-alkoxysilane (3-Aminopropyl) dimethoxymethylsilane with tetra-alkoxysilane tetraethyl orthosilicate. The flexible linear Si O Si segments produced by di-alkoxysilane are inserted into the tetra-alkoxysilane derived rigid three-dimensional silicon-oxygen domains, as confirmed by spectroscopic characterizations. This unique structure alleviates the shrinkage stress during curing and enables the formation of crack-free xerogels. Therefore, the hybrid siloxane oligomer can invade into the interior of weathered stone to form one three-dimensional continuous network to strengthen its fragile structure. As a result, the flexible-rigid hybrid siloxane oligomer outperforms both as-made polysiloxane consolidant and commercial consolidant for the consolidation of the weathered Tianlong Mountain Grottoes stone samples. The consolidation treatment was evaluated in terms of effectiveness (Leeb hardness, ultrasonic velocity and compressive strength) and compatibility (pore size distribution, water vapor transmission rate and color variation). Following the treatment, the consolidated samples demonstrate remarkable improvements in mechanical properties, reaching a Leeb hardness of 410 HL and a compressive strength of 8.98 Mpa. Additionally, permeability and color variation of the stone after consolidation are all within acceptable ranges. The results confirm the positive consolidation performance of the flexible-rigid hybrid siloxane oligomer on weathered Tianlong Mountain Grottoes stone, indicating promising practical applications. A novel flexible-rigid hybrid siloxane oligomer that can produce flexible linear Si O Si segments mediated rigid three-dimensional silicon-oxygen domains during curing is designed by the self-catalyzed copolymerization of di-alkoxysilane with tetra-alkoxysilane. This unique structure enables the formation of the crack-free xerogel on flat substrate and the continuous three-dimensional reinforcement network within the porous weathered stone, resulting in a superior consolidation effect for the weathered Tianlong Mountain Grottoes stone heritage. [Display omitted] [ABSTRACT FROM AUTHOR]

In this research work, a real case of failed ASTM A860 WPHY 65 long elbow pipe coated with inorganic zinc ethyl silicate primer is collected from a treatment facility to investigate the root causes of its failure, which was reported after approximately 28 months of use. The failure was investigated using visual observations, metallurgical analysis using optical emission spectroscopy, mechanical testing, X‐ray diffraction of corrosion product, chemical analysis of sewage and corrosion rate test of the elbow using a three‐electrode potential technique, fractographic analysis using scanning electron microscope along with computational analysis to confirm the results. Through the testing, it was observed that severe depletion in the strength can be attributed to erosion–corrosion caused by various impurities present in the sewage, leading to the generation of corrosion pits and turbulent eddies and stresses generated due to sudden changes in fluid flow direction along with gases present in sewage reacting with a base metal. Various failure mechanisms that have led to pipe failure are discussed in this paper, along with a listing of preventive measures to delay it. [ABSTRACT FROM AUTHOR]

Mechanical strength is an important factor that affects and limits the life of surface antireflective (ARC) coatings such as optical lenses, photovoltaic panels, and liquid crystal displays. In this work, a network-structured silica sol was prepared using tetraethyl orthosilicate (TEOS) and methyltriethoxysilane as silicon sources. Triethoxy(1H,1H,2H,2H-nonafluorohexyl)silane (C4FTES) was used to modify the acid-catalyzed silica sol. Finally, the mixed sol was plated on the surface of polymethyl methacrylate by impregnation-pulling method. The coating obtained after drying at 100°C showed a maximum transmittance of 97.98% in the visible wavelength range (400–800 nm). The coating still maintained good optical properties after undergoing various wear-resistant tests such as sandpaper abrasion and cotton ball friction. Moreover, the pencil hardness test of the coating improved from 5B to 3H after it was modified by short-chain perfluoroalkyl groups (C4FTES). This work required only low-temperature treatment without calcination to prepare a silicon-based ARC coating formed by copolymerization of C4FTES and TEOS, and the mechanical properties of the coating meet actual needs. This easy-to-operate preparation method greatly expands the application scope of silicon-based ARC coatings in the field of heat-sensitive materials. The polymethyl methacrylate (PMMA) substrate is coated with a fluorine-containing coating with a network structure, which greatly improves the transmittance and surface hardness of the substrate. [ABSTRACT FROM AUTHOR]

This study provides and investigates the fabrication of graphene oxide (GO) sheets decorated with chitosan nanoparticles (CSNP) through the hybridizing of GO and CS, by the addition of tetraethyl orthosilicate (TEOS) as a cross-linker agent. The fabricated GO-CSNP composite was characterized using several advanced techniques. Furthermore, various parameters affect the sorption of Sr(II), such as contact time, pH, initial concentration, dosage, temperature, and coexisting ions. The experimental results were in accordance with the pseudo-second-order reaction. The interaction mechanism between Sr(II) and GO-CSNP composite was accurately described by the Langmuir isotherm model with a maximum adsorption capacity of 473.93 mg/g. The GO-CSNP composite demonstrated exceptional selectivity for the sorption of Sr(II) over Y(III) at a high concentration ratio of 10:1 for Sr2+ to Y3+, respectively. Furthermore, the GO-CSNP adsorbent demonstrated considerable potential as a highly effective sorbent for the adsorption of Sr(II), Mo(VI), Cd(II), and Cs(I) ions. The results revealed that the prepared composite was effectively capable of removing various fission products. [ABSTRACT FROM AUTHOR]

Among the countless routes for renewable hydrogen (H2) production, Biogas Dry Reforming (DR) has been highlighted as one of the most promising for the circular bio-economy sector. However, DR requires high operating temperatures (700 °C–900 °C), and, for greater efficiency, a thermally stable catalyst is necessary, being, above all, resistant to coke formation, sintering, and sulfur poisoning. Mesoporous metallic catalysts, such as nickel (Ni) supported on silica, stand out due to their high catalytic activity concerning such characteristics. In this regard, the presented work evaluated the influences of the nickel addition stage during the synthesis of mesoporous catalyst type Si-MCM-41. Two different catalysts were prepared: catalyst A (Ni/Si-MCM-41_A), synthesized through the in situ addition of the precursor salt of nickel (Ni(Ni(NO3)2·6H2O) before the addition of TEOS (Tetraethyl orthosilicate) and after the addition of the directing agent; and catalyst B (Ni/Si-MCM-41_B), resulting from the addition of the precursor salt after the TEOS, following the conventional methodology, by wet impregnation in situ. The results evidenced that the metal addition stage has a direct influence on the mesoporous structure. However, no significant influence was observed on the efficiency concerning BDR, and the conversions into H2 were 97% and 96% for the Ni/SiMCM-41_A and Ni/Si-MCM-41_B catalysts, respectively. [ABSTRACT FROM AUTHOR]

A functionalized modified metal–organic framework material, T-MOF-808, was synthesized through hydrophobic modification with tetraethyl orthosilicate (TEOS) and chlorotrimethylsilane (TMCS). Then a supported oxidative desulfurization catalyst, [C12Py]3(NH4)3Mo7O24/T-MOF-808(s), was prepared by using a heteropoly acid ionic liquid as the active component. The prepared samples were characterized using FT-IR, XRD, SEM, TEM, XPS, etc. [C12Py]3(NH4)3Mo7O24/T-MOF-808(s) was used in the oxidative desulfurization of dibenzothiophene (DBT). At the same time, the effects of different loadings of the active component, oxygen sulfur ratios, reaction temperatures, and reaction time were also investigated. [C12Py]3(NH4)3Mo7O24/T-MOF-808-15%(s) could oxidize 100% of DBT in 40 min at 60 °C. Significantly, the catalyst exhibited no discernible decline in catalytic activity after 14 runs. In addition, the efficiency of sulfur removal was 85.76% in actual diesel oil. It was found that the cooperative impact of hydrophobic modification and electron transfer makes an important contribution to the high activity. The hydrophobic modification provides a novel approach for using MOF materials in the oxidative desulfurization process. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of silicon-containing precursors on the facile synthesis of Ni-phyllosilicate, Stöber SiO 2 , tetraethyl orthosilicate (TEOS), sodium metasilicate (Na 2 SiO 3 ⋅9H 2 O) was used. Na 2 SiO 3 successfully reacts with the nickel nitrate to form nickel phyllosilicate at ambient temperature, owing to its strong basicity and easy hydrolysis to generate intermediates of H 4 SiO 4 and Ni(OH) 2. Stöber SiO 2 and TEOS can only convert to Ni-phyllosilicate with the assistance of NH 4 F and urea, because of the limitation of intermediates formation. The Na 2 SiO 3 -based Ni-phyllosilicate NiPs-M-12 shows the highest catalytic activity for CO 2 methanation among all the samples, whose maximum CO 2 conversion reaches 71.0% at 450 °C, 0.1 MPa, 60 L g−1·h−1 with a TOF CO2 of 2.6 ± 0.1 × 10−3 s−1 and activation energy of 83.19 kJ mol−1. The active intermediates of *HCOO and *CO are observed by in-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS) analysis, which can be hydrogenated to CH 3 O species with the further hydrogenation to produce the target products CH 4 and H 2 O. It also displays high long-term stability up to 100 h with high anti-sintering property. In conclusion, the recognition of the interrelationships of silicon-containing precursors and the formation of intermediates can shed light on the facile synthesis of Ni-phyllosilicate with high catalytic performance. • The room-temperature synthesis of Ni-phyllosilicate was proposed. • The properties of silicon-containing precursors were important for Ni-phyllosilicate synthesis. • The strong basicity and easy hydrolysis of Na 2 SiO 3 were the main reasons for the formation of intermediates of H 4 SiO 4 and Ni(OH) 2. • The Na 2 SiO 3 -based Ni-phyllosilicate showed high catalytic activity and stability. [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles (NPs) were synthesized using a cost-effective co-precipitation method. Magnetite NPs were encapsulated with silica via the modified Stober Method. Tetra ethyl ortho silicate (TEOS) was hydrolyzed and condensed with ethanol and H2O solution. Stable and biocompatible NPs were synthesized for biomedical applications such as bioseparation. This study expresses the NPs that can potentially be used in the bioseparation of toxic protein isolations and targeted drug delivery. X-ray diffraction verified the phase pattern having crystals like Fd-3m cubic space. Scanning electron microscopy (SEM) images identified the spherical-shaped NPs having size ranges from 15nm to 30nm for magnetite NPs and 20–40nm for silica-coated magnetite NPs. Fourier transform infrared spectroscopy (FTIR) confirmed the bond spectrum peak at 549cm−1 and 562cm−1 for magnetite NPs and silica-coated magnetite NPs, respectively. UV–Visible analysis observed the band absorptions above 250nm for magnetite and above 300nm for silica-coated magnetite NPs. This research suggests an easy way to use silica-coated Magnetite NPs for bioseparation at room temperature. [ABSTRACT FROM AUTHOR]

Alternative anode materials with increased theoretical specific capacities are under scrutinity as a replacement to graphite in lithium‐ion batteries (LiBs). Silicon oxides offer increased capacities compared to graphite and do not suffer the same level of material expansion as pure Si. Consequently, they are an intermediate commercial anode material, on the pathway toward pure Si anodes. In this study, stable Silica/carbon (SiO2/C) nanofibers are successfully developed from tetraethyl orthosilicate (TEOS) using poly(vinylpyrrolidone) (PVP). The fibers show excellent stability after calcination, with silica evenly dispersed within the fibers exhibiting a surface area of 327 m2 g−1. This study demonstrates that the electrochemical performance of SiO2/C composite anodes is significantly influenced by the silica content. SiO2/C composites with ≈68 at% SiO2 achieve reversible capacities of 315.6 and 300.9 mAh g−1, after the 2nd, and 800th cycles, respectively, at a specific current of 100 mA g−1, with a remarkable capacity retention of 95.3%. In a second stage, lignin is added as a potential nanostructuring agent. The addition of lignin to the sample reduces the amount of silica without significantly impacting its performance and stability. Tailoring the composition of SiO2/C composite anodes enables stable capacity retention over the course of hundreds of cycles. [ABSTRACT FROM AUTHOR]

In this study we investigate the use of in situ bioprocessing for the production and surface modification of bacterial cellulose (BC) with silicon additives. The surface properties and tensile strength of the BC were studied and compared with plain BC. The effect the modification exhibited on the survivability of the bacteria was assessed by optical density measurements and found that the addition of the modification marginally slowed growth in the case of Tetramethyl orthosilicate (TMOS) and did not affect the growth in the case of Tetraethyl orthosilicate (TEOS). Characterisation of the modified BC was carried out using FTIR, EDX and confirmed the presence of silicon in the material. The width of fibres in the microstructure of BC was measured using SEM. Two different silicon modifications were used to modify the BC, it was shown that the TMOS modification decreased the tensile strength but that the TEOS increased the tensile strength of the BC fibres compared to plain BC. In addition, we found that the washing conditions of 1% NaOH (w/v), industrial methylated spirit (IMS), and deionised water (DI) showed some impact on the properties of the samples, particularly the IMS produced a reduced contact angle in the modified samples. However, the contact angle increased in the case of TEOS modification with the NaOH wash. In conclusion this study shows a novel method of modifying BC materials in-situ using silicon additives for increased tensile strength and the potential for tuneable hydro interactions. [ABSTRACT FROM AUTHOR]

Silica (SiO2) plays a major key ingredient in producing products such as toothpaste, ceramics, and paints, to name a few, as it acts as a stabilizing agent, filler and additive. Due to its excellent properties, the use of high-purity SiO2 in industrial applications is favourable. Unfortunately, high-purity SiO2 is expensive. Tetraethyl Orthosilicate (TEOS) is an example of a SiO2 precursor that is costly and harmful, yet frequently employed. This paper provides a short review of the advantages of biowaste materials as SiO2 precursors and their role as fillers in the fabrication of superhydrophobic coating. Researchers nowadays are attempting to lower the expense of employing high-purity SiO2 by extracting silica from biowaste using many methods such as acid leaching and alkali treatment as this option is highly sustainable. The growth of agricultural industries is exponential due to the increase in biowaste production. Therefore, this is one of the ways to utilize the use of biowaste in combatting the environmental issues regarding excess biowaste and receding pure resources. SiO2 from biowaste also can be utilized as filler and used to develop superhydrophobic coating, providing numerous potential applications. [ABSTRACT FROM AUTHOR]

Due to the ecocompatibility with carbonate‐based substrates, Ca(OH)2 nanoparticles are currently used for cultural heritage conservation such as wall paintings. However, the nano Ca(OH)2 still suffers from different forms and poor uniformity, limiting its application potential. Also, there is a lack of systematic comparative studies between nano Ca(OH)2 and the commonly used wall painting reinforcement materials. In this study, homogeneous hexagonal nano Ca(OH)2 particles with a size of ≈100 nm are successfully prepared through the convenient chemical liquid phase method and by utilizing surfactants to control the growth. The resulting nano Ca(OH)2 is less agglomerated and has superior crystalline morphology, prolonged suspension time, and more suitable carbonation time in comparison to commercial Ca(OH)2 materials. Additionally, the reinforcement effect of the resulting nano‐Ca(OH)2 with that of the commonly used pigment layer reinforcement materials such as AC33, B72, Tetraethyl orthosilicate, WPU (Waterborne polyurethane) and commercial Ca(OH)2 is systematically compared. The synthesized nano Ca(OH)2 penetrated wall painting blocks to a depth of 683 µm, three times deeper than commercial Ca(OH)2, achieving moderate color deviation, higher flexural strength (0.529 MPa), and bond strength (1.105 mg cm−2), thus highlighting its potential in wall painting reinforcement and expanding its application scope. [ABSTRACT FROM AUTHOR]

By way of the sol–gel chemical synthesis method, it is possible to synthesize SiO2 nanoparticles with a defined specific particle size, a surface area, and a defined crystal structure that can be effectively used as a nanoadsorbent to remove various organic dyes. SiO2 nanoparticles were synthesized by the sol–gel method using sodium silicate (Na2SiO3) by a green method without using a tetraethyl orthosilicate (TEOS) precursor, which is very expensive and highly toxic. This sol–gel process involves the formation of a colloidal suspension (sol) and solid gelation to form a network in a continuous liquid phase (gel). In addition, it requires controlled atmospheres. XRD indicates the presence of an amorphous phase with a diffraction angle of 2θ = 23°, associated with SiO2. UV-Vis spectroscopy reveals an absorbance value in the region of 200 nm to 300 nm, associated with SiO2 nanoparticles. The application as a nanoadsorbent to remove dyes was measured, and it was found that the nanoparticles with the best performance were those that were synthesized with pH 7, showing a 97% removal with 20 mg of SiO2 nanoparticles in 60 min. Therefore, SiO2 nanoparticles can be used as a nanoadsorbent, using a low-cost and scalable method for application to remove methylene blue in an aqueous medium. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Almaty Technological University is the property of Almaty Technological University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, two treatments were performed on deteriorated volcanic tuff stone samples taken from a 16th-century historical structure: (i)solventless mixtures of ethyl silicates (TEOS) tetraethoxysilane consolidation product followed by application of two different silane-siloxane-based water-repellent commercial products (TEOS+WR1 and TEOS+WR2), (ii) two different silane-siloxane based water repellent commercial products (one emulsion (WR2) and the other solution (WR1) based). This study aims to determine the effectiveness, compatibility, durability and service life of the studied conservation treatments on tuff stones. Therefore, colorimetric measurements, chemical and petrographic analyses (XRF, XRD, SEM-EDS) and physical and mechanical characterization tests were performed on the treated and untreated samples. Additionally, accelerated weathering tests were performed in the laboratory on all treated stones to determine the long-term performance of the chemical treatments. After these weathering tests, physical (water absorption under atmospheric pressure, water capillarity coefficient, water vapour permeability) and mechanical (ultrasonic pulse velocity, flexural and compressive strength) property tests were performed again and according to the results, the performance change in the efficiency indexes (TEI,%) was calculated. All results were compared and discussed. The results showed the best performance of TEOS+WR1 treatment in improving the consolidating and water-repellency abilities of tuff stone samples. However, the least colour change in the colour measurements after the treatments was in the treatments using emulsion-type water-repellent products. [ABSTRACT FROM AUTHOR]

Introduction: The material for exposed pulp treatment is calcium hydroxide (Ca(OH)2), although there are still some disadvantages. Composites with components of gelatin, chitosan, carbonated hydroxyapatite, and Tetraethyl orthosilicate (TEOS) were used to develop the material to obtain optimal quality. Nestin is a marker for differentiation of odontoblast and expressed in irritated odontoblasts. This study evaluated Nestin expression in the dental pulp after applying gelatin-chitosan-TEOS-Ca(OH)2 composite material. Materials and methods: There were 30 Wistar rats divided into two groups, namely the treatment and control groups, with 15 rats in each group. The maxillary first molar tooth was opened using diamond bur No. 010 to the depth of the pulp. The gelatin-chitosan-TEOS-Ca(OH)2 composite was applied in the treatment group, while the control group used Ca(OH)2, followed by temporary fillings. The expression of Nestin was evaluated after 1,3,5,7, and 14 days of application using immunohistochemistry method under light microscopy with 64x and 160x magnifications. Three replication was taken for each evaluation time. Results: A positive expression seen in both the treatment and control groups. The pulp area beneath the irritated tissue showed positive expression of Nestin, especially in the odontoblasts and their processes, pulp cells near positive of the odontoblasts, and flat cells attached to the dentin. The treated group showed weaker Nestin expression than the control group. Conclusion: The gelatin-chitosan-TEOS-Ca(OH)2 composite material has potential as an exposed pulp medicament. After applying the gelatin-chitosan-TEOS-Ca(OH)2 composite to the exposed pulp, the positive Nestin expression indicates a pulp tissue regeneration process. [ABSTRACT FROM AUTHOR]

Ag@SiO2 core–shell nanoparticles (NPs) have attracted extensive attention for their excellent surface-enhanced Raman scattering (SERS)-fluorescence (SEF) and their potential applications in sensing, biomedicine, and imaging. The thickness of silica shell plays a crucial role in determining the SERS-SEF properties. However, a few studies have been made to synthesize Ag@SiO2 core–shell NPs with controllable thickness of silica shell and systematic research about the optimized SERS-SEF enhancement. Here, Ag@SiO2 core–shell NPs were prepared by a modified one-pot synthetic method via reducing AgNO3 using formaldehyde in the presence of cetyltrimethylammonium chloride and sequentially hydrolyzing tetraethyl orthosilicate (TEOS). The effects of the type of surfactant and the concentrations of NaOH and AgNO3 on the size and morphology of the resulting Ag@SiO2 core–shell NPs were systematically investigated. The thickness of the silica shell could be finely tuned from 9.3 to 38.9 nm by easily adjusting the amount of TEOS. The crystal violet molecule was used for examining SERS and SEF properties of Ag@SiO2 core–shell NPs with different SiO2 thicknesses. The current work will provide guidance for further understanding the growth mechanism of Ag@SiO2 core–shell NPs and how the thickness of silica shell affects the SERS-SEF properties. [ABSTRACT FROM AUTHOR]

Epoxies derived from natural sources as an alternative to conventional petroleum-based epoxy resins have been used in sustainable coating applications. This study aims to create corrosion-resistant bio-based epoxy nanocoatings in the context of sustainable development. For this purpose, vegetable oil-based epoxy resins from cardanol and soybean oil were prepared. The structure of bio-based epoxies was confirmed by FTIR and 1H-NMR spectroscopy techniques. The epoxy functional silane precursor is synthesized from tetraethyl orthosilicate and (3-Glycidyloxypropyltrimethoxysilane by means of the sol–gel method. Amine curing agent and inorganic silica skeletons as polyhedral oligomeric silsesquioxanes and sol–gel precursor were added to the epoxy adduct and then cured. The curing kinetics of the formulations was followed by a differential scanning calorimeter. The chemical, mechanical, thermal, and anti-corrosive properties of the prepared coatings were investigated using various tests. The sustainable epoxy-based nanocoatings exhibited higher mechanical and thermal stability. In addition, the nanocoatings showed excellent corrosion resistance without the use of any anti-corrosive agent. The prepared green sustainable coatings will provide a more sustainable way to prepare bio-based coatings. [ABSTRACT FROM AUTHOR]

At present, Ag nanoparticles have been widely used as Raman substrates, but their easy oxidation and aggregation have limited practical applications. In order to address the above problems, firstly, tetraethyl orthosilicate as a precursor was applied to synthesis silver coated with silica dioxide nanoparticles (Ag@SiO2). As a result, the surface of Ag nanoparticles is uniformly coated with a thin layer of SiO2 in order to solve the easy oxidation problem without adversely affecting their surface‐enhanced Raman scattering (SERS) performance. Furthermore, Ag@SiO2 nanoparticles were electrostatically deposited onto polyamide (PA) films to form a two‐dimensional PA‐Ag@SiO2 film substrate, thus resolving nanoparticle agglomeration issues and further improving the repeatability of the entire system. As can been from the SERS detection results obtained from the probe molecules and pollutants, the Raman signal on the PA‐Ag@SiO2 thin film substrate has a good degree of sensitivity, stability, and repeatability. [ABSTRACT FROM AUTHOR]

Surface treatments applied to new or existing concrete elements provide effective protection against intrusive media, helping to reduce maintenance and repair costs. However, technical data are scarce on documenting the field performance of concrete surface treatments in cold regions with aggressive conditions, particularly for emerging nano-modified coatings. To address this gap, a field study was conducted to evaluate the efficacy of different plain and nanocomposites as surface treatments on 34-year-old concrete bridge deck sections in Winnipeg, Manitoba, Canada. The study compared neat resins (silane, methyl methacrylate, and ethyl silicate) and nano-based coatings (nano-silica 50 % solution, silane with nano-clay, and silane with nano-silica at 2.5 % and 5 % by mass) on cores extracted from cracked and uncracked concrete prepared with two surface preparation methods. The experiments compared the initial performance (transport properties and microstructural features) of coated concrete to its performance after one year under service conditions. The results indicate that coatings play a significant role in providing protection against intrusive media and reducing maintenance efforts and costs. Among the coatings tested, silane and methyl methacrylate offered the least improvement in concrete protection with time in cold regions. The 50 % nano-silica solution provided moderate performance, whereas ethyl silicate and silane nanocomposites demonstrated superior performance in reducing transport properties regardless of the surface preparation methods. Given the improvement in long-term durability and cost, silane nanocomposites with a 2.5 % loading ratio may be a viable treatment method for concrete flatwork in cold regions.

The surface characteristics of nanoparticles have a huge impact on adsorption effects. In this paper, thiol‐functional mesoporous silica nanospheres (MSNs−SH) are successfully prepared through simple one‐step hydrolysis and co‐condensation of tetraethyl orthosilicate and (3‐mercaptopropyl) triethoxysilane with hexadecyltrimethylammonium bromide and sulfobetaine 12 as dual‐template. The obtained MSNs−SH have high surface area (1260 m2 g−1), accessible mesopores (2.2 nm), great pore volume (1.7 cm3 g−1), and uniform adjustable diameter (90 nm). Furthermore, the diameter and pore‐size of MSNs−SH can be controlled via adjusting the ethanol content in the synthesis system. MSNs−SH exhibit a fast adsorption kinetics, marked adsorption capacity of cationic rhodamine B (RB 534.2 mg g−1), and remarkable selective adsorption for cationic dyes. Theoretical analysis reveals the adsorption behavior of RB on MSNs−SH follows the Langmuir isotherm models and pseudo‐second‐order kinetic. Additionally, the thermodynamic results indicate that the adsorption process is a spontaneous process driven by temperature. The results demonstrate that MSNs−SH are greatly potential for effectively removing cationic dyes from wastewater, with the advantages of simple preparation, high adsorption performance and perfect selectivity. [ABSTRACT FROM AUTHOR]

We studied a gradient anti-oxidation coating of C/C composite materials for aircraft brake discs with a simple process and low costs. The gradient coating consists of two layers, of which the inner layer is prepared with tetraethyl orthosilicate (Si (OC2H5)4), C2H5OH, H3PO4 and B4C, and the outer layer is prepared with Na2B4O7.10H2O, B2O3, and SiO2 powder. The experimental results show that after being oxidized at 700 °C for 15 h, the oxidation weight loss of the sample with the coating was only −0.17%. At the same time, after 50 thermal cycles in air at 900 °C, the sample's oxidation weight loss was only −0.06%. We conducted the 1:1 dynamic simulation test for aircraft brake discs, and the brake disc did not oxidize, thus meeting the requirements for aircraft use. In addition, the anti-oxidation mechanism of the coating was analyzed via scanning electron microscopy (SEM), X-ray diffraction (XRD), differential thermal analysis (DSC-TGA), and high-temperature in situ SEM. [ABSTRACT FROM AUTHOR]

The coupling effect of flexural loading and wetting–drying cycles on chloride transmission in silane composite emulsion-protected concrete is presented in this paper. Graphene oxide/isobutyltriethoxysilane (GS) and tetraethyl orthosilicate/isobutyltriethoxysilane (TS) composite emulsion was prepared to obstruct the penetration of chloride, and the influence of flexural loading and exposure time on the protective effect were mainly considered. The results show that the content and diffusion coefficient of chloride are affected significantly by flexural loading, exposure age, and protective emulsion. Loads with different stress ratios affect the internal transmission of chloride by changing the compactness of concrete. The prolongation of the exposure age leads to the accumulation of chloride, thereby increasing the internal chloride contents of concrete. The GS/TS composite emulsion reacts with the hydration products to form the hydrophobic layer, which can significantly prevent the penetration of chloride. In particular, the protective performance of GS under low stress ratios is better than that of TS, while under high stress levels, TS has better resistance to chloride erosion. Relatively speaking, the long-term protective effect of GS is better than that of TS. [ABSTRACT FROM AUTHOR]

A comprehensive methodology for fabricating and characterizing the tetraethyl orthosilicate (TEOS) modified exfoliated boron nitride (eBN) reinforced epoxy resin (EP) composites has been demonstrated. The functionalized eBN was synthesized by solution‐mixing followed by alkali‐assisted hydrothermal reaction. The composites with various filler loadings (0, 5, 10, and 15 wt.%) were fabricated using solution casting method. The fundamental features of the composites were examined through tensile and bending properties, thermal properties, and anticorrosion properties. The synthesized TEOS‐eBN was utilized to improve the dispersibility and compatibility with the EP resin, which played a crucial role in improving the thermal conductivity as well as thermomechanical properties of the composites. The incorporation of filler in the EP matrix improved the thermomechanical as well as anticorrosion properties. The tensile and flexural tests were carried out according to ASTM D‐638 and ASTM‐D790, respectively. We discovered that the 5 wt.% of TEOS‐eBN in EP showed the optimum thermomechanical properties. The tensile strength and Tg were improved by ~74.71 and ~16.8% at 5 wt.% loading. The improved thermomechanical and anticorrosion properties of all the composites showed the potential to be efficient heat‐releasing material for thermal management and coating applications in automotive industries. Highlights: Tetraethyl orthosilicate (TEOS)‐exfoliated boron nitride (eBN) was synthesized by alkali‐assisted hydrothermal and solution mixing method.The composite specimens exhibited excellent thermal conductivity.The thermomechanical and anticorrosion performance were remarkably improved.Optimal thermomechanical properties were obtained at 5% filler content. [ABSTRACT FROM AUTHOR]

A series of mixed-anion Fe(NH2trz)3(BF4)2−x(SiF6)x/2 spin crossover complexes is obtained modifying the reaction time but also using an increase amount of tetraethyl orthosilicate as the source for the production and the incorporation of SiF62− competing with the BF42− anions present in the mother solution. The increase of the SiF62− anion inclusion to the detriment of the BF4− counterpart induces a shift of the temperature transition toward high temperatures leading to interesting bistability properties around room temperature with T1/2 spanning from 300 K to 325 K. Moreover, the implementation of a solid–liquid post synthetic modification approach from the Fe(NH2trz)3(BF4)2 parent complex with identical TEOS proportions and under certain experimental conditions lead systematically to the same Fe(NH2trz)3(BF4)1.2(SiF6)0.4 composition. This compound presents an abrupt spin crossover behaviour with a narrow hysteresis loop just above room temperature (320 K), which is stable under thermal cycling and along time with no specific storage conditions. Such crystalline powder sample incorporates homogeneous rod-shaped particles whose formation and physical properties can be followed simultaneously using infra-red spectroscopy, dynamic light scattering (DLS), transmission electronic microscopy (TEM) and optical reflectance. The observation of a stabilized single ca. 800 nm population of mixed-anion particles starting from insoluble various sizes (from nano- to microscale) Fe(NH2trz)3(BF4)2 particles supports the key role of the solvent (water molecules) on the separation, the reactivity and the reorganization of the 1D iron-triazole chains forming the packing of the structure. [ABSTRACT FROM AUTHOR]

In this work, we present an advancement in the encapsulation of lithium yttrium fluoride-based (YLiF4:Yb,Er) upconversion nanocrystals (UCNPs) with silica (SiO2) shells through a reverse microemulsion technique, achieving UCNPs@SiO2 core/shell structures. Key parameters of this approach were optimized to eliminate the occurrence of core-free silica particles and ensure a controlled silica shell thickness growth on the UCNPs. The optimal conditions for this method were using 6 mg of UCNPs, 1.5 mL of Igepal CO-520, 0.25 mL of ammonia, and 50 μL of tetraethyl orthosilicate (TEOS), resulting in a uniform silica shell around UCNPs with a thickness of 8 nm. The optical characteristics of the silica-encased UCNPs were examined, confirming the retention of their intrinsic upconversion luminescence (UC). Furthermore, we developed a reliable strategy to avoid the coencapsulation of multiple UCNPs within a single silica shell. This approach led to a tenfold increase in the UC luminescence of the annealed particles compared to their nonannealed counterparts, under identical silica shell thickness and excitation conditions. This significant improvement addresses a critical challenge and amplifies the applicability of the resulting UCNPs@SiO2 core/shell structures in various fields. [ABSTRACT FROM AUTHOR]

The kinetics of the synthesis of silica nanoparticles (<50 nm) has been studied under the conditions of heterogeneous hydrolysis of tetraethoxysilane (TEOS) using L-arginine as an alkaline catalyst. The rates of silica formation have been determined in a temperature range of 10–95°C at catalyst concentrations of 6–150 mM. It has been shown that the activation energy of the process depends on catalyst concentration and varies in a range of 21.5–13.9 kJ/mol, while decreasing linearly with increasing concentration of L-arginine in the system. The criterion of maintaining the monodispersity has been estimated for SiO2 particles being grown "onto seeds." The density of submicron-sized silica particles has been experimentally determined as depending on the annealing temperature. Within a temperature range of 200–1000°C, the particle density varies from 2.04 to 2.20 g/cm3. [ABSTRACT FROM AUTHOR]

A yellow-emitting cationic iridium(III) complex [(dfppy)2Ir(TBD)]PF6 (TBD: N4,N4′-bis(3-(triethoxysilyl)propyl)-[2,2′-bipyridine]-4,4′-dicarboxamide; dfppy: 2-(2,4-difluorophenyl)pyridine) containing hydrolysable alkoxysilanes was synthesized. Then, a series of silica-based hybrid nanospheres with diameters of around 400 nm was prepared via the hydrolysis of this complex together with tetraethyl orthosilicate (TEOS, a silica source). When the amount of the complex used was 5.0 wt%, hybrid nanospheres showed the best photoluminescence (PL) properties, relative to the PL quantum yield of pure solid [(dfppy)2Ir(TBD)]PF6 (12.7%), that of hybrid nanospheres increased to 26.2%. Moreover, the thermal decomposition temperature (Td) of pure solid [(dfppy)2Ir(TBD)]PF6 was 331 °C, the Td of the complex in hybrid nanospheres increased to 447 °C. However, the yellow light emission was almost unchanged and was still located at 500–750 nm with a maximum wavelength (λem,max) of 577 nm. Under the excitation of blue-emitting chips (λem,max ≈ 455 nm), cold/neutral/warm white light-emitting diodes (WLEDs) with good luminous quality can all be fabricated using these hybrid nanospheres as phosphors in epoxy resin at different blending concentrations. Compared with two or three iridium(III) complexes being contained in silica-based particles as phosphors as described in literatures, in this study, silica-based hybrid nanospheres covalently containing only one yellow-emitting cationic iridium(III) complex as phosphors provide a more effective and simpler method for preparation high-performance WLEDs. [ABSTRACT FROM AUTHOR]

Organically coated steels are widely used in applications in which they are subjected to the natural environment and therefore require excellent corrosion resistance. Organic clearcoats are typically employed as a barrier that improves the overall corrosion resistance; however, they are typically derived from fossil fuel-based feedstock. A more sustainable alternative could be possible using sol–gel coatings. The application of a simple tetraethoxysilane (TEOS)-based sol–gel was applied to polyurethane-coated steels using a spray coater. The concentration of TEOS was altered to produce coatings containing either 2.5% or 10%. The 10% TEOS resulted in dense, homogeneous coatings that offered a significant improvement in corrosion resistance compared to an uncoated substrate. Whereas the 2.5% TEOS coatings were inhomogeneous and porous, which indicated a limitation of concentration required to produce a uniform coating. The successful demonstration of using a simple TEOS-based coating to improve the corrosion resistance of organically coated steel highlights the potential for further investigation into the use of sol–gels for these applications. [ABSTRACT FROM AUTHOR]

In recent concrete research, a novel category of coatings has emerged: polymers/nanoparticles blends. The efficacy of such coatings warrants extensive examination across various concrete mixtures, particularly those incorporating high-volume supplementary cementitious materials (SCMs) to mitigate carbon footprints, an industry imperative. This study used three vulnerable concrete mixtures to assess the effectiveness of ethyl silicate and high-molecular-weight methyl methacrylate blended with 2.5% and 5% halloysite and montmorillonite nano-clay. Findings from physical, thermal, and microstructural analyses confirmed vulnerabilities in concretes with a high water-to-binder ratio (0.6) under severe exposure conditions, notably with high SCM content (40% and 60% fly ash and slag, respectively). Neat ethyl silicate or high-molecular-weight methyl methacrylate coatings inadequately protected those concretes against physical salt attacks and salt–frost scaling exposures. However, the incorporation of halloysite nano-clay or montmorillonite nano-clay in these polymers yielded moderate-to-superior concrete protection compared to neat coatings. Ethyl silicate-based nanocomposites provided full protection, achieving up to 100% improvement (no or limited surface scaling) against both exposures, particularly when incorporating halloysite-based nano-clay at a 2.5% dosage by mass. In contrast, high-molecular-weight methyl methacrylate-based nano-clay composites effectively mitigated physical salt attacks but exhibited insufficient protection throughout the entire salt–frost scaling exposure, peeling off at 15 cycles. [ABSTRACT FROM AUTHOR]

Silicon oxycarbide (SiOC) coatings were prepared through isothermal chemical vapor co-deposition by using two precursors of hexamethyldisilane (HMDS) and tetraethyl orthosilicate (TEOS). The microstructure, composition and the protectiveness on C/C composite against oxidation of the coatings prepared at temperatures ranging from 1423 K to 1563 K and pressures ranging from 500 Pa to 1200 Pa were investigated, respectively. After oxidation, cracks and defects were formed in the coatings of all conditions due to the volume shrinkage of amorphous SiO 2 crystallization and the mismatch of thermal expansion coefficient (CTE) between SiOC coatings and substrate. The most oxidation-resistant SiOC coating was obtained at 1563 K and 500 Pa, which exhibited the lowest weight loss rate of 4.87 % after 12 h of oxidation at 1673 K in air condition. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Two fluorescent molecularly imprinted polymers (MIPs) were developed for pepsin enzyme utilising fluorescein and rhodamine b. The main difference between both dyes is the presence of two (diethylamino) groups in the structure of rhodamine b. Consequently, we wanted to investigate the effect of these functional groups on the selectivity and sensitivity of the resulting MIPs. Therefore, two silica-based MIPs for pepsin enzyme were developed using 3-aminopropyltriethoxysilane as a functional monomer and tetraethyl orthosilicate as a crosslinker to achieve a one-pot synthesis. Results of our study revealed that rhodamine b dyed MIPs (RMIPs) showed stronger binding, indicated by a higher binding capacity value of 256 mg g−1 compared to 217 mg g−1 for fluorescein dyed MIPs (FMIPs). Moreover, RMIPs showed superior sensitivity in the detection and quantitation of pepsin with a linear range from 0.28 to 42.85 µmol L−1 and a limit of detection (LOD) as low as 0.11 µmol L−1. In contrast, FMIPs covered a narrower range from 0.71 to 35.71 µmol L−1, and the LOD value reached 0.34 µmol L−1, which is three times less sensitive than RMIPs. Finally, the developed FMIPs and RMIPs were applied to a separation-free quantification system for pepsin in saliva samples without interference from any cross-reactors. [ABSTRACT FROM AUTHOR]

The paper describes synthesis of ZSM-5 zeolite using two amorphous synthetic aluminosilicates prepared by different methods: one involved precipitation from solutions of sodium silicate and aluminum sulfate, and the other was based on sol–gel synthesis using tetraethyl orthosilicate and aluminum nitrate. The method for the preparation of amorphous aluminosilicates was shown to affect the morphology, dispersion, and porous structure of ZSM-5 crystals. [ABSTRACT FROM AUTHOR]

To overcome the drawback of carbon nanofibers (CNFs) such as the low energy density and low specific capacitance as electrode for supercapacitors, SiO 2 /PANI@CNFs composite was prepared by layer-by-layer (LbL) assembly technique, in which the SiO 2 served as a component for improving capacitive behavior. Polyaniline (PANI) is used as nucleation site for synthesizing SiO 2 particles as well as active material for improving capacitance. In this study, SiO 2 particles were synthesized using biosilicification process as a bioinspired, rapid, and facile synthetic route for SiO 2 particles at ambient temperature and pressure, etc. To elucidate effect of SiO 2 on the electrochemical properties, SiO 2 /PANI@CNFs samples were prepared by varying concentration ratio of tetraethyl orthosilicate (TEOS) to CNFs. It was observed that the specific surface area and the capacitance are highly dependent on the TEOS concentration. The capacitance of the composite prepared at the TEOS concentration of 0.19 mmol reaches 412 F g−1 at the current density of 1 A g−1. These results are attributed to increased specific surface area from interstitial voids between SiO 2 particles and hydrophilic nature of SiO 2 particles, which offers sufficient channels for rapid ion diffusion and leads easy accessibility to the active sites for the electrochemical reaction between electrode and aqueous electrolyte. Due to its excellent electrochemical and biocompatible properties, bioinspired SiO 2 inorganic material will promote the development of energy storage devices in biomedical and environmental electronics. [ABSTRACT FROM AUTHOR]

The aim of this research is to study the main deterioration aspects and evaluate the treatment of mural painting at the Tomb of Qen-Amun TT93 dating back to the 18th dynasty, New Kingdom (c. 1550-1069 BC.), in the Theban Necropolis, on the west bank of the Nile in Luxor. In this study, the surface of deteriorated mural paintings were investigated using PLM, TEM investigation of the eggshell nanoparticles, XRD analysis, FTIR spectroscopy, and SEM-EDX. To our knowledge, it is the first report on the mixture of the ethyl silicate and the egg shell nanoparticles application of mixture for the treatment of deteriorated mural painting surfaces in the Tomb of Qen-Amun TT93. The samples were collected from the fragment of wall painting, painted with the depiction of two women, Tomb of Qen-Amun (TT93). The obtained results showed that the structures fragment of wall painting included three layers from the top to bottom: yellow pigment, fine plaster, coarse plaster composed of quartz, clay minerals, iron oxides, and plant fibers. The results illustrated that the mixture was highly effective at consolidating cracks, and the appearance of the treated surfaces was. [ABSTRACT FROM AUTHOR]