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Marques Ana C. Rojas-Hernandez Rocío Estefanía Almeida Rui M. 《Journal of Sol-Gel Science and Technology》2021,99(1):1-12
Journal of Sol-Gel Science and Technology - In this paper, structural, optical, and electrical features of undoped and copper-incorporated nickel oxide (Cu/NiO) films with different mole ratios... 相似文献
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G. Ahmed I. Petkov S. Gutzov 《Journal of inclusion phenomena and macrocyclic chemistry》2009,64(1-2):143-148
New optical materials containing coumarin (3-(3-(4-(dimethylamino)phenyl)propenoyl)-2H-chromen-2-one) in silica are reproducibly prepared by a sol–gel technique and characterized with UV/Vis and luminescence spectroscopy. The incorporation of the coumarin molecules in the silica gels is monitored with UV/Vis spectroscopy. The coumarin doped gels change their color with time which is attributed to a protonation of the dimethylamino group of the coumarin molecules during aging of the gels and is proved by UV/Vis spectroscopy. The process of protonation of the dimethylamino group is described as a second order reaction. The luminescence spectra of the coumarin doped gels at room temperature also are given. 相似文献
4.
G. Della Giustina M. Guglielmi G. Brusatin M. Prasciolu F. Romanato 《Journal of Sol-Gel Science and Technology》2008,48(1-2):212-216
We report the use of an epoxy based hybrid sol–gel material as negative resist for electron beam lithography (EBL). The matrix has been prepared starting from 3-glycidoxypropyltrimethoxysilane as specific organic–inorganic precursor and the synthesis has been strictly controlled in order to preserve the epoxy ring and to obtain a proper inorganic cross-linking degree. The film has been exposed to an electron beam, inducing the polymerization of the organic part and generating the film hardening. Preliminary results of a resolution test on the synthesized epoxy based sol–gel material, performed with electron beam lithography, are presented. Structures below 300 nm were achieved. The direct nanopatterning of this hybrid sol–gel system simplify the nanofabrication process and can be exploited in the realization of photonic devices. A demonstration has been carried out doping the hybrid films with commercial Rhodamine 6G and reproducing an already tested laser structure. 相似文献
5.
The advantages of the sol–gel technology are undoubtedly simplicity and versatility. It enables to obtain for example oxides
in the form of layers, powders, monoliths or fibers. These materials can be successfully applied for sensing purposes due
to their properties such as transparency, porosity, and high surface areas. In this article, the basis of operation of mainly
optical and semiconductor sensors are presented. A brief overview of various kinds of sensors is submitted. The utility of
optical fibers and planar waveguides in these systems is discussed. The paper contains also some results obtained by the authors
in the field of thin film-based sensors. 相似文献
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Alexander M. Macmillan Dalibor Panek Colin D. McGuinness John C. Pickup Duncan Graham W. Ewen Smith David J. S. Birch Jan Karolin 《Journal of Sol-Gel Science and Technology》2009,49(3):380-384
By using the fluorescent dye 6-propionyl-2-(N,N-dimethylamino) naphthalene (PRODAN) to monitor methanol generated during tetramethyl orthosilicate polymerization we have
optimised the encapsulation of protein in silica sol–gel monoliths with respect to completion of hydrolysis and distillation
in order to remove methanol such that protein can be added without denaturation. A minimum of 24 h at +4 °C was found to be
required before hydrolysis is complete and 3–5 min of vacuum distillation at 50 °C and 300 mbar needed to remove methanol
before the gel is formed. The biocompatibility of a tetramethyl orthosilicate sol–gel monolith was demonstrated by preserving
the trimer protein allophycocyanin (APC) in its native form for up to 500 h. This obviates the previously essential requirement
of covalently binding the trimer together in order to prevent dissociation into monomers and has enabled observation of native
APC trimer in a sol–gel pore for the first time down to the single molecule level using combined fluorescence spectroscopy
and confocal microscopy. The higher stability afforded by the protocol we describe could impact on the application of sol–gel
materials to single-molecule studies of wider bearing such as protein folding and aggregation. 相似文献
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I. Berra L. Irusta M. J. Fernández-Berridi Y. R. de Miguel 《Journal of Sol-Gel Science and Technology》2009,49(1):19-28
Novel phenoxy-silica hybrid materials (with 3 wt.% SiO2) have been synthesized using different synthetic procedures. Differential scanning calorimetric (DSC) (Tg), FT-IR and transmission electron microscopy (TEM) results, as well as thermal and mechanical properties, are reported for
these hybrids, which can be classified into three different groups, depending on the number of components synthesized in situ.
Best results in terms of homogeneity (TEM) and mechanical properties have been obtained when the sol–gel process has been
carried out in the presence of a phenoxy resin modified with a pendant alkoxysilane monomer.
相似文献
Y. R. de MiguelEmail: |
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Shang-Ru Zhai Li Zhang Bin Zhai Qing-Da An 《Journal of Sol-Gel Science and Technology》2012,61(1):23-33
Thiol-functionalized sol–gel materials with porous structures were successfully prepared via co-condensation of tetraethoxysilane, (3-mercaptopropyl)-trimethoxysilane, polymeric polymethylhydrosiloxane in the absence of traditional structure-directing agents under proposed basic conditions. The dependence of textural characteristics on the preparation parameters were investigated employing various techniques as such N2 adsorption/desorption isotherms, SEM, TG-DTG, FT-IR and solid state 29Si MAS NMR measurements. It was shown by these characterizations that thiol-functional groups have been successfully introduced into the porous network and the loadings could be tuned by adjusting the content of corresponding precursor in the gel system. Besides, the as-prepared samples exhibited high surface areas, large pore volume, tunable pore diameters and favorable thermal stability. Adsorption experiments indicated that thiol-incorporated materials have selective adsorption ability toward heavy metal ions from aqueous solutions, and a high capacity in adsorbing heavy metal ion of Pb2+ (up to 99.4%) was observed under optimized experimental conditions. 相似文献
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O. Yu. Sinelshchikova S. A. Petrov N. V. Besprozvannykh S. K. Kuchaeva E. A. Vlasov 《Journal of Sol-Gel Science and Technology》2013,68(3):495-499
A new method of sol–gel synthesis has been proposed for fabrication of functional materials with ramsdellite and hollandite types of crystal structure in the following oxide systems: Me2O–Me′2O3–Me″O2 (Me = Li, K; Me′ = Ga, Cr, Fe, In; Me″ = Ti, Sn). The formation of titanates with ramsdellite-type structure is shown to achieve at the temperature range of 250–650 °C, when gel combustion occurs. This allows fabrication of materials with high specific surface area. The ramsdellite phases and stannate hollandites are shown to form in the temperature range of 1,100–1,150 °C. Thus our method gives the possibility to reduce the thermo-temporal parameters of synthesis for this class of materials. 相似文献
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X-rays investigations have been shown to reveal important information regarding material features and the formation mechanism
of mesostructured materials. Small angle X-ray scattering (SAXS) analysis performed using a synchrotron source has been very
important in the optimization of the organization of mesoporous coatings obtained by evaporation induced self-assembly (EISA).
The interaction between X-rays and ordered mesoporous films has only recently been reported, and new knowledge has been developed
to use this external radiation source to tune the local material properties. Here we discuss the recent developments in X-ray
lithography combined with sol–gel synthesis to pattern mesostructured and hierarchical porous coatings including the ability
to tailor functionalized surfaces. 相似文献
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A new dyeing process of sol–gel silica doped with direct dyes is investigated for improving color strength (K/S value) and dyeing fastness. Cotton fabrics are dyed in this direct dye silica solution. The results indicate that the K/S value of C.I. Direct Blue 86 and C.I. Direct Red 23 are enhanced by 12.8% and 16.8%, respectively. For C.I. Direct Blue 86, the washing staining fastness is improved by half a grade, and the rubbing fastness and the washing change
fastness are enhanced by one grade, respectively. Compared to the fabric fixed with fixing reagent MMF-1, the K/S value is improved by about 23.7% and the wet rubbing fastness and washing change fastness are enhanced by half a grade. The
formation of uniform continuous layers on the fiber surface dyed with direct dye silica solution is revealed by video microscope,
and the calculated sol–gel weight gain on the fabric is 4.6%. 相似文献
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Formation and characterization of phosphate-modified silicate materials derived from sol–gel process
Anastasia Epiphanova Oleg Magaev Olga Vodyankina 《Journal of Sol-Gel Science and Technology》2012,61(3):509-517
Phosphate-containing silicate materials prepared using sol–gel method from Si(OC2H5) were investigated at the variation of the amount of phosphate modifier from 5 to 50 wt% in term of P2O5. Chemical composition, textural and structural properties of these materials were characterized by FTIR-spectroscopy, TEM,
X-ray diffraction and nitrogen adsorption. It was shown that the materials posse monomodal pore size distribution of 5–20 nm
for the samples dried at 100 °C and 40–60 nm for the specimens calcined at 600 °C. The mean pore size and surface area depended
on the amount of phosphoric acid. Before the stage of high temperature treatment phosphoric acid, introduced into the structure
of the materials as a modifying agent, was uniformly distributed inside a porous space of the material and was not chemically
bonded with silicate. After high temperature treatment both chemical interaction of silicate with phosphate, providing the
formation of silicate-phosphate structures, as well as redistribution of free modifier from the bulk of granules to their
surface took place. The polyphosphate layer is formed on the material surface closing the internal porous space. However,
in this case a part of the phosphate modifier remains chemically unbound to SiO2 structure. 相似文献
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Ang Qian Yee Chan Florence Tan Pei Chin Low Siew Chun 《Journal of Sol-Gel Science and Technology》2018,86(1):226-238
Journal of Sol-Gel Science and Technology - Molecularly imprinted polymer (MIP) is of great attention in biomimetic recognition systems due to its selective molecular recognition towards any guest... 相似文献
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Inorganic gels formed using the sol–gel process are promising hosts for the encapsulation of living organisms and the design
of cell-based biosensors. However, the possibility to use the biological activity of entrapped cells as a biological signal
requires a good understanding and careful control of the chemical and physical conditions in which the organisms are placed
before, during, and after gel formation, and their impact on cell viability. Moreover, it is important to examine the possible
transduction methods that are compatible with sol–gel encapsulated cells. Through an updated presentation of the current knowledge
in this field and based on selected examples, this review shows how it has been possible to convert a chemical technology
initially developed for the glass industry into a biotechnological tool, with current limitations and promising specificities. 相似文献
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Yutie Bi Liping He Yong Zhang Shuaijie He Hongbo Ren Lin Zhang 《Journal of Sol-Gel Science and Technology》2014,72(2):415-420
In this thesis, we will elaborate on the sol–gel process during the preparation of monolithic copper-based aerogel. The microstructure of the copper-based aerogel appears to be various due to the different amounts of raw materials, such as polyacrylic acid, propene oxide, deionized water (H2O) and copper(II) chloride (CuCl2) in the sol–gel process. The proper molar ratios between these reactants play a crucial factor in mediating the morphology of the aerogel. The aerogels are characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy and Brunauer–Emmett–Teller methods. The combined results indicate that the copper-based aerogel shows a typical three-dimensional porous structure with a large surface areas about 568 m2/g, and the skeleton structure of the aerogel is composed of a large number of primary particles with the size about a few nanometers. 相似文献
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Lidia Armelao Gregorio Bottaro Laura Bovo Chiara Maccato Eugenio Tondello Francesca Anselmi Sara Bersani Paolo Caliceti 《Journal of Sol-Gel Science and Technology》2011,60(3):352-358
The conjugation between probe biomolecules and inorganic nanoparticles has been studied. Three different and biologically
relevant proteins, bovine serum albumin (BSA), lysozyme (LSZ) and Ribonuclease A (RNAseA), have been selected as model systems
because of their difference in size and isoelectric point. Zinc oxide nanoparticles, synthesized via sol–gel, have been thoroughly
characterized by X-ray Photoelectron Spectroscopy, Scanning Electron Microscopy and X-ray Diffraction, and subsequently used
as platforms for immobilization of the biomolecules. The interaction of the three proteins with the ZnO surface was performed
in phosphate buffer solutions at pH 7.2 in order to mimic physiological fluids and was investigated through fluorescence experiments.
The obtained results indicate that conjugation of BSA, LZS and RNAseA on the oxide nanoparticles was mostly dictated by the
overall charge of the different proteins. Electrostatic bonds dominate the formation of the protein/ZnO conjugates, whereas
the size of the proteins seems to play a negligible role under the adopted experimental conditions. 相似文献
18.
Predoana Luminita Atkinson Irina Karaj Dániel Attila Odhiambo Vincent Otieno Bakos László Péter Nagyné Kovács Teodóra Pandele-Cusu Jeanina Petrescu Simona Rusu Adriana Szilágyi Imre M. Pokol György Zaharescu Maria 《Journal of Thermal Analysis and Calorimetry》2021,143(4):2893-2900
Journal of Thermal Analysis and Calorimetry - In the literature data, several papers reported the synthesis by various chemical or physical methods of the SrCu2O2 (SCO) having possible applications... 相似文献
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Catalin Ilie Spataru Violeta Purcar Marius Ghiurea Constantin Radovici Gabriela Stanga Dan Donescu 《Journal of Sol-Gel Science and Technology》2013,65(3):344-352
Modifications to the refractive indices of meso-structured organic–inorganic films caused by variations in the mole fraction of precursors in ethanolic solutions were investigated. The refractive indices were dependent on the mole fraction of C16TMS (hexadecyltrimethoxysilane) and of the C16TMS/TMOS (tetramethoxysilane) (1/1) mixture in ethanol. The dependency was determined to be nonlinear, and the phenomenon was attributed to self-assembly caused by the long alkyl groups (C16) on the C16TMS. Changes in the maximum decreasing rate of dn/dx values [(dn/dx)max—for dn/dx estimation, the curves from Fig. 1 were associated with a polynomial; using a dedicated program, dn/dx was calculated; maximum values of dn/dx were taken into account and were included in Table 1)] were used to distinguish the behavior of alcoholic precursor mixtures. In the case of using pyrene as a fluorescent probe, the ratio between two peaks from the pyrene emission spectra (I1/I3) strongly decreased as hydrophobic micro-surroundings formed due to the self-assembly process. The UV–VIS spectra of a cationic dye solution, R6G, was studied because dilute solutions of the dye in equilibrium form measurable ratios of dimers and monomers. The absorbance was modified as micro-surroundings with different polarities were formed. These three methods demonstrated that nano-structuration was present prior to the occurrence of the sol–gel process. The combination of C16TMS with other alkyltrialkoxysilane precursors having hydrocarbon chain lengths between C1 and C8 provided further evidence for a nonlinear dependence of the refractive indice and fluorescence spectra of pyrene. The properties of the final hybrids obtained by the sol–gel process were significantly affected by the precursor hydrocarbon chain lengths. DSC, XRD and FTIR measurements were used to show the plasticizing phenomena of C16 as other alkyltrialkoxysilanes (i.e., C1–C8) were added. Fig. 1
Variation of the refractive index with the mole fraction of the precursor mixtures 相似文献
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Josephs RD Koeber R Linsinger TP Bernreuther A Ulberth F Schimmel H 《Analytical and bioanalytical chemistry》2004,378(5):1190-1197
Analytical difficulty and the economic importance of controlling mycotoxin levels in food and feed led the Community Bureau of Reference (BCR) to prepare a series of certified reference materials (CRM) for various mycotoxins. Because of the wide acceptance of these CRM and the need to ensure the comparability and traceability of measurements in the future it is necessary to prepare and certify new batches of mycotoxin reference materials (RM). In the following text two different approaches for evaluation of the characterisation uncertainty of CRM will be compared using the certification of aflatoxin M1 (AfM1) in milk powder as an example. The conventional approach is based on evaluation of characterisation exercise data; the alternative approach is based on measurement uncertainties of the employed analytical methods. Because laboratories are using totally different approaches to estimate the measurement uncertainties, combination of the uncertainties obtained from the participating laboratories was not recommended. Therefore, a new integrated approach for assessment of the measurement uncertainties of the analytical methods on the basis of additional data collected during the characterisation exercise will be described. The conventional approach was found to be the most appropriate and economical approach to evaluate the characterisation uncertainty as a characterisation exercise must be performed anyway to establish the property values of candidate (C)RM, irrespective of whether or not reliable measurement uncertainties can be provided by the laboratories. An integrated approach for assessment of measurement uncertainties based on additional characterisation data as applied here to enable use of an uncertainty-based approach provides more information but is too time-consuming and cost-intensive to become common practice. 相似文献