Influence of the composition and structure of epoxy siloxane matrix on the spectral behavior of the nile red dye: II. Sol-gel system based on tetraethoxysilane and glycidoxypropyltrimethoxysilane

The organic-inorganic materials with fluorescence properties are synthesized in the form of gels and xerogels from tetraethoxysilane and glycidoxypropyltrimethoxysilane by the sol-gel method. The concentration of the introduced Nile Red dye is 2.2 × 10^?6 M. The fluorescence spectra of the prepared materials are measured and analyzed as a function of the ratio between the initial components forming the sol-gel epoxy siloxane matrices. The assumption regarding the structure of the synthesized hybrids is made invoking the data obtained by Fourier-transform IR spectroscopy and atomic-force microscopy.     

Development of the technology for preparing and storing hydrogen with the use of nanostructured materials for an autonomous integrated wind power plant

This paper reports on the results of investigations into the design of an operating prototype of the power plant for the production and accumulation of hydrogen. The objective of this work is to develop technologies of intermediate storage of hydrogen with subsequent generation of an electric power due to the electrochemical processes occurring in fuel cells with an efficiency of no lower than 90%. The power plant is based on the wind power plant, which operates using an integrated software-hardware system for control over the power regime of the entire technological process. New membrane and catalytic materials prepared by the solgel method are used as functional components of fuel cells.     

Synthesis and Physicochemical Properties of Nanopowders and Ceramics in a CeO<Subscript>2</Subscript>–Gd<Subscript>2</Subscript>O<Subscript>3</Subscript> System

Nanopowders with a composition of (СeO₂)_1–x(Gd₂O₃)_x (x = 0.03, 0.05, 0.07, and 0.10) are synthesized by the coprecipitation method using cryotechnologies. The coherent scattering region (CSR) of the powders is 10–14 nm and the specific surface area is 70–81 m²/g. Based on the powders, ceramic nanosized materials with CRS of 64–71 nm are obtained. The dependence of the phase composition, microstructure, and electrical transport properties of the obtained samples on the Gd₂O₃ content is established. In a CeO₂–Gd₂O₃ system, a solid solution with the composition of (CeO₂)_0.90(Gd₂O₃)_0.10 has the highest ionic conductivity with the transfer number of ions of t_i = 0.74 at a temperature of 700°C. It is shown that ceramics of this composition can be used as a solid electrolyte of intermediate-temperature fuel cells due to their physicochemical characteristics.     

Bioactive coatings based on nanodiamond-modified epoxy siloxane sols for stone materials

Using a sol-gel process, we have prepared bioactive organic-inorganic hybrid coatings based on epoxy siloxane sols modified with detonation nanodiamond. The microstructure of the coatings was studied by scanning electron microscopy. The coatings were tested—under both laboratory and urban conditions—for bioactivity against the mold fungi most frequently encountered in the air in large cities. The results suggest that such coatings are potentially attractive for protecting historic monuments from biodeterioration.     

Characteristic Features of the Change in the Zeta-Potential of the Surface of Synthetic Aluminosilicates of a Kaolinite Group with Different Morphologies

Glass Physics and Chemistry - The dependence of the zeta-potential of the surface of the synthesized under hydrothermal conditions silicates of the subgroup of kaolinite (Al2Si2O5(OH)4 ?...     

Using the Sol–Gel Technology for the Treatment of Barley Seeds

Silica sols obtained by acidic or alkaline hydrolysis of tetraethoxysilane in an excess of water or ethanol in the presence of a number of salts and/or acids are used to treat the surface of barley seeds. The surface state and the elemental composition of the seeds are studied before and after their treatment in silica sols. The conditions of the sol–gel synthesis of silica sols, their effect on the state and chemical composition of the seed surface, and the sowing characteristics are analyzed. The plant’s resistance to phytopathogen, the causative agent of root rot is studied.     

Synthesis of Iron Oxide Magnetic Nanoparticles and Their Effect on Growth,Productivity, and Quality of Tomato

Glass Physics and Chemistry - The influence of the structure, phase composition, textural and colloidal properties of magnetic iron oxides nanoparticles in the form of aqueous suspensions with a...     

Investigation of the surface of silica films doped with Fe and Co

The silica films prepared from tetraethoxysilane sols and doped with iron and/or cobalt nitrates are investigated using atomic-force microscopy and Auger electron spectroscopy. The influence of the metal nature on the surface morphology of the films and the specific features of the distribution of doping elements over the film thickness are demonstrated.     

Kinetics of structuring in the sol-gel systems based on tetraethoxysilane with organic additives: I. Sols

This paper reports on the results of rheological investigations into the kinetics of gelation of the sol-gel systems based on a water-alcohol solution of tetraethoxysilane (TEOS) modified by a number of metal salts and organic polyhydroxyl compounds, such as glycerol, poly(ethylene glycol) (PEG-300), and hyperbranched aliphatic complex polyol polyethers (HBP-49, HBP-64). It is demonstrated that, at a dispersed phase concentration of approximately 10 wt %, water-ethanol sol-gel systems containing 2–4 g/l of high-molecular additives possess a shear strength and are characterized by anomalous properties in their flow. The gelation time of sols in the presence of organic additives is affected by the ratio between the numbers of OH^– hydrophilic and CH₃ hydrophobic groups in the polymer molecule, the concentration of the introduced additive, and the electrolyte multivalence. The presence of metal salts enhances the structuring effect of polymers.Original Russian Text Copyright © 2005 by Fizika i Khimiya Stekla, Movchan, Urev, Khamova, Tarasyuk, Potapov, Shilova, Klimenko, Shevchenko.     

Comparative Study of Powders Based on the ZrO<Subscript>2</Subscript>–Y<Subscript>2</Subscript>O<Subscript>3</Subscript>–СeO<Subscript>2</Subscript> System Obtained by Various Liquid Phase Methods of Synthesis

Using the liquid-phase methods of synthesis—the coprecipitation of hydroxides and the hydrothermal method—mesoporous xerogels are obtained based on the ZrО₂–Y₂О₃–CeО₂ system with 5–8-nm particles and powders (after the heat treatment of xerogels at 600°C) with a coherent scattering region (CSR) size of 9 to 10 nm and S_sp = 96–156 m²/g. After calcination at 1400°C, the powders are transformed into tetragonal solid solutions with a CSR size of 65 nm in the synthesis by the coprecipitation method, and they are transformed into solid solutions with a CSR size of 84 nm with a high degree of tetragonality of c/a = 1.438–1.431 in the synthesis by the hydrothermal method.