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1.
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
2.
Some recent works made in our group on inorganic nanophosphors are briefly reviewed in this paper. We first present the synthesis of highly concentrated semiconductor quantum dot colloids allowing the extension of the well-known oxide sol–gel process to chalcogenide compounds. Secondly, we show the synthesis and the chemical functionalization of lanthanide-doped insulator nanoparticles. In particular, the annealing process of these particles at high temperature leads to highly bright nanocrystals, which can be used as biological luminescent labels or for integration in transparent luminescent coatings. Finally, we consider luminescent transition metal clusters, which combine the inorganic structure of nanoparticles with the monodispersity and the easy functionalization of the organic molecules. Emphasis is put on the original thermochromic luminescence properties of copper iodide clusters trapped in siloxane-based films. 相似文献
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Geik Ling Teoh Kong Yong Liew Wan A. K. Mahmood 《Journal of Sol-Gel Science and Technology》2007,44(3):177-186
Abstract Alumina nanofibers of high aspect ratio with surface area of >300 m2 g−1 has been prepared successfully in bulk quantities by the sol–gel method. The synthesis parameters including the binary water–alcohol
solvent system to aluminium isopropoxide ratio, pH, type of solvent and aging temperature affect the uniformity and formation
of nanofibers. It is proposed that alumina nanofibers were formed by the curling of the nanosheets upon condensation after
the hydrolysis. The phase evolution of alumina nanofibers from pseudoboehmite to α phase has been shown by XRD and FTIR. 27Al NMR investigations show that the Al atoms are six and four coordinated. The morphology of the alumina nanofibers does not
change much as the calcination temperature was increased. In addition, the average pore size increases and the BET surface
area decreases as a function of calcination temperature. The thermal behavior of alumina nanofibers was investigated by TGA.
Graphical Abstract
相似文献
5.
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
6.
This study investigated the effects of different additives and precursors on the catalytic activity of laccase entrapped in
sol–gel silica. It was found that the laccase catalytic activity and stability of sol–gel laccase could be enhanced if the
entrapment was performed in the presence of additives such as PVA, PEG and APTS. The use of TEOS as a precursor showed slightly
higher laccase catalytic activity compared to TMOS. The PVA as an additive showed a better catalytic activity enhancement
compared to the PEG and APTMS with the optimum PVA concentration of 0.03 mg/mL. The optimal temperatures of sol–gel laccase
without and with additives were found to be at 40 and 27°C, respectively. After 70 days of storage at 27°C, the catalytic
activity of the immobilized sol–gel laccase with additives maintained its catalytic activity compared to only 30% of its original
catalytic activity for the sol–gel laccase without additives. 相似文献
7.
Mohammad Mizanur Rahman Aleya Hasneen Won-Ki Lee Kwon Taek Lim 《Journal of Sol-Gel Science and Technology》2013,67(3):473-479
Waterborne polyurethane (WBPU) sol–gel adhesives were prepared through a prepolymer process followed by a sol–gel reaction of (3-aminopropyl)triethoxysilane (APTES). The terminal amine group of APTES reacted with the NCO group of the prepolymer, and the ethoxy group created Si–O–Si branching by hydrolysis and condensation reactions in water at the dispersion step. Water swelling (%), tensile strength and Young’s modulus of the synthesized WBPU sol–gel adhesives were improved by increasing APTES content. Synthesized WBPU sol–gel adhesives were used for bonding nylon fabrics. A significant improvement in adhesive strength was recorded, and the potential for good adhesive strength under water at moderately high temperature (up to 75 °C) was observed with 6.84 mol% APTES in WBPU sol–gel adhesives. 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
10.
Boris Mahltig Dirk Fiedler Anja Fischer Paul Simon 《Journal of Sol-Gel Science and Technology》2010,55(3):269-277
Antimicrobial textile materials were produced by sol–gel coatings with embedded biocidal compounds. For preparation a sol–gel
procedure was used, starting from pure silica sols and 3-glycidyloxypropyltriethoxysilane (GLYEO) containing silica sols.
These sols were modified with silver compounds, hexadecyltrimethyl-ammonium-p-toluolsulfonat (HTAT) and copper compounds, respectively. The investigations were performed on viscose fabrics as function
of the concentration of biocidal compounds and of thermal treatment of textile after dip-coating between 80 up to 180 °C.
The use of modified silica coatings leads to a decreased growth of fungi (Aspergillus niger) and bacteria (Bacillus subtilis and Pseudomonas putida) with increasing amount of the biocide embedded in the coating. The addition of GLYEO supports the biocidal effect of the
coatings and enhances the stability of the coating solutions. For preparation of antimicrobial silica coatings the biocides
silver, copper or HTAT can be used alone but the combination of these compounds leads to enhanced results against both fungi
and bacteria. Therefore silica sols containing a combination of different types of biocides may be used for antimicrobial
modification of textiles in some practical applications. For industrial applications the here presented coating solutions
are especially advantageous, because of 90% water content in the solvent. 相似文献
11.
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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Anita R. Taulbee-Combs Matthew J. Bachus Kamila M. Wiaderek William H. Steinecker Zechariah D. Sandlin James A. Cox Gilbert E. Pacey 《Journal of Sol-Gel Science and Technology》2010,56(2):134-140
Terahertz (THz) time-domain reflectance spectroscopy is evaluated as a technique for nondestructive analysis of sol–gels over
the first week of aging without directly contacting or disturbing the sol–gels. In the sol–gels analyzed, tetramethyl orthosilicate
(TMOS) is the precursor and polyamidoamine (PAMAM) dendrimers are incorporated into each of two sol–gel sample groups; a third
control group contains no dendrimer. The study reports data acquired during sol–gel aging in contrasting humidity and ventilation
conditions and determines statistically whether the inclusion of a particular dendrimer and/or the humidity and air circulation
of the environment produce significant differences in the THz reflectance intensity observed throughout the first week of
sol–gel aging. The results of this study are correlated with previous studies of the same three species analyzed using AFM,
impact testing and nitrogen adsorption. The correlations are used to interpret the THz reflectance intensity differences between
the sol–gel groups studied using the previously reported results from established methods of analysis regarding the influence
of each dendrimer on polymer density, pore size and distribution, and homogeneity of the resulting amorphous silica monoliths. 相似文献
14.
Sol–gel preparation conditions and optical spectra between 220 and 900 nm of Sm3+ doped silica materials are discussed. It is demonstrated that the intensity of the O2? → Sm3+ charge transfer transition at 285 nm depends on gelation conditions due to samarium related defects in the silica matrix. The room temperature sol–gel transformation and drying of Sm3+ doped samples is followed using UV/Vis spectroscopy. The rate of densification of samarium doped silica materials at room temperature is calculated from increase of the intensity of Sm3+ f–f absorption transitions during time. 相似文献
15.
Dominik L. Jürgen-Lohmann Christoph Nacke Leonardo C. Simon Raymond L. Legge 《Journal of Sol-Gel Science and Technology》2009,52(3):370-381
Although the use of silica sol–gels for protein entrapment has been studied extensively our understanding of the interactions
between the immobilization matrix and the entrapped biomolecules is still relatively poor. Non-invasive in situ spectroscopic
characterization is a promising approach to gain a better understanding of the fundamentals governing sol–gel immobilization
of biomolecules. This work describes the application of Fourier transform infrared (FTIR) microscopy to determine the influence
of modifying the sol–gel hydrophobicity, by varying the content of the organically modified precursor propyltrimethoxysilane
(PTMS), on the distribution and structure of three model proteins (lysozyme [EC 3.2.1.17], lipase [EC 3.1.1.3] and bovine
serum albumin (BSA)) in silica sol–gel thin films. FTIR analysis of the overall immobilized protein positional distribution
showed a Gaussian type distribution. FTIR microscopic mapping however, revealed that the spatial distribution of proteins
was heterogeneous in the sol–gel thin films. When this positional information provided by FTIR microscopy was taken into account,
areas of high protein concentration (clusters) were found and were not found to be homogeneously distributed. The shape of
these clusters was found to depend on the type of protein entrapped, and in some cases on the composition of the sol–gel.
Positional analysis of the distribution of the organically modified precursor PTMS in relation to the protein distribution
was also conducted. The localized concentration of PTMS was found to positively correlate with the protein concentration in
the case of lipase and negatively correlate in the case of lysozyme and BSA. These results indicate that lysozyme and BSA
concentration was higher in areas of low hydrophobicity, while lipase concentration was higher in areas of high hydrophobicity
within the sol–gel. Additionally, as determined by peak shape analysis of the amide I peak a higher PTMS content appeared
to conserve protein structure in high concentration clusters for lipase. In contrast, lysozyme and BSA, appeared to retain
their structure in high concentration clusters better at lower PTMS contents. A hypothesis speculating on the nature of the
hydrophobic/hydrophilic interactions between the proteins and the sol–gel domains as the reason for these differences is presented. 相似文献
16.
?. Kment I. Gregora H. Kmentová P. Novotná Z. Hubi?ka J. Krysa P. Sajdl A. Dejneka M. Brunclíková L. Jastrabík M. Hrabovsky 《Journal of Sol-Gel Science and Technology》2012,63(3):294-306
The photoinduced self-cleaning and super-hydrophilic properties of titania (TiO2) coated glasses are considered to be utilized in many applications. The photocatalytic activity of titania is inherent to the glass composition and to the deposition method. Particularly sodium ions diffused to the titania film from the substrate have tremendous impact on its crystallinity. The deposition method influences surface, structure, and the density of the film. This study aims to provide new findings regarding the mechanism of crystallization of sol?Cgel synthesized titania and its thin films deposited by means of two different methods (dip-coating and spin-coating) onto the glass substrate with a high content of sodium ions (soda-lime glass) and without sodium ions (quartz glass). The main attention is devoted to Raman spectroscopy and Raman point-to-point mapping of the films. The content and the chemical state of the sodium ions were judged using the XPS. It is shown that the dip-coating method led to dense compact material. In this case the crystallization is localized in randomly distributed centers of nucleation. Contrary the spin-coated samples embodied a web-like pattern of cracks, from which the crystallization proceeds throughout the film. Additionally SEM, AFM, XRD, GDS, UV?CVIS methods were performed to support the results. 相似文献
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A. Zalga Z. Moravec J. Pinkas A. Kareiva 《Journal of Thermal Analysis and Calorimetry》2011,105(1):3-11
The preparation and characterization of the M′–M′′–O nitrate–tartrate (M′ = Ca, Ba, Gd and M′ = W, Mo) precursor gels synthesized
by simple, inexpensive, and environmentally benign aqueous sol–gel method is reported. The obtained gels were studied by thermal
(TG/DSC) analysis. TG/DSC measurements revealed the possible decomposition pathway of synthesized M′–M′′–O nitrate–tartrate
gels. For the synthesis of different metal tungstates and molybdates, the precursor gels were calcined at different temperatures
(650, 800, and 900 °C). According to the X-ray diffraction (XRD) analysis data, the crystalline compounds CaMo1-x
W
x
O4 doped with Ce3+ ions, BaMo1-x
W
x
O4 doped with Eu3+ ions and Gd2Mo3O12 were obtained from nitrate–tartrate gels annealed at 650–900 °C temperatures. The XRD data confirmed that the fully crystalline
single-phase powellite, scheelite, or Gd2(MoO4)3 structures were formed already at 650 °C. Therefore, the suggested sol–gel method based on the complexation of metal ions
with tartaric acid is suitable for the preparation of mixed tungstates–molybdates at relatively low temperature in comparison
with solid-state synthesis. 相似文献
19.
D. R. Bae Y.-J. Lee D. K. Kim S. W. Lee K. S. Chang G.-R. Yi G. Lee 《Journal of Sol-Gel Science and Technology》2014,71(3):606-610
An organic molecule was used as a surfactant for nanoparticle synthesis in liquid phase. However, residual molecules on the surface of the nanoparticles limit their catalytic applications, because the interaction of a reactant with the nanoparticle surface is interrupted. Therefore, it is favorable for catalytic applications that the organic molecule used in the synthesis of nanoparticles only induces a sol–gel reaction of the metal precursors and the formation of nanoparticles and hardly adheres to the resulting nanoparticles. Herein, we report surfactant-free and high-surface area maghemite nanostructures via nonhydrolytic sol–gel reaction. Using Fe(acetylacetonate)3 as an iron precursor and hexylamine as a solvent and growth inhibitor, Fe2O3 nanoparticles were generated by nonhydrolysis of the iron complex and condensation at 140 °C under an air atmosphere. Characterization revealed monodisperse nanoparticles with an average size of 2.3 nm and a crystalline phase of maghemite. Residual hexylamine is hardly observed, and thus their specific surface area is 403.7 m2/g. An experimental comparison of the Fe2O3 synthesis with hexylamine and benzylamine indicates that the cone angle of an organic molecule is an important factor in the synthesis of nanoparticles with a small size and high surface area. 相似文献
20.
Chen-Chen Ji Mao-Wen Xu Shu-Juan Bao Chang-Jun Cai Rui-Ying Wang Dian-Zeng Jia 《Journal of Solid State Electrochemistry》2013,17(5):1357-1368
The electrochemical performances of the α-, γ-, and δ-MnO2 with different crystallographic structures were systematically investigated in 0.5 mol/L Li2SO4, 0.5 mol/L Na2SO4, 1 mol/L Ca(NO3)2, and 1 mol/L?Mg(NO3)2 electrolytes. The results showed that the electrochemical performances of the manganese dioxides depended strongly on the crystallographic structures of MnO2 as well as the cation in the electrolytes. Because the δ-MnO2 consists with layers of structure and the interlayer separation is 7 Å, which is suitable for insertion/extraction of some alkaline and alkaline–earth cations, the δ-MnO2 electrode showed the higher specific capacitance than that of α-MnO2 and γ-MnO2. We also found that the α-, γ-, and δ-MnO2 electrodes in the Mg(NO3)2 electrolyte showed a higher specific capacitance, while all the α-, γ-, and δ-MnO2 electrodes in the Li2SO4 electrolyte exhibited a better cycle life. The reason for the different behavior of Li+ and Mg2+ during the charge/discharge process can be ascribed to the charge effect of the cations in the electrolytes. The ex situ X-ray diffraction (XRD) and long-time cyclic voltammogram measurements were used to systematically study the energy storage mechanism of MnO2-based electrodes. A progressive crystallinity loss of the materials is also observed upon potential cycling at the oxidized states. A reasonable charge/discharge mechanism is proposed in this work. 相似文献