共查询到20条相似文献,搜索用时 15 毫秒
1.
Hasan Guleryuz Ingeborg Kaus Claudine Filiàtre Tor Grande Mari-Ann Einarsrud 《Journal of Sol-Gel Science and Technology》2010,54(2):249-257
Deposition of silica thin films on silicon wafer was investigated by in situ mass measurements with a microbalance configured
for dip coating. Mass change was recorded with respect to deposition time when the substrate was fully immersed in the silica
sol. Mass gain during deposition was higher than predicted from monolayer coverage of silica nano particles. This implied
that deposition was facilitated by gelling of the nanoparticles on the substrate. The rate of deposition was enhanced by increasing
the particle concentration in the sol and by decreasing the particle size from 12 to 5 nm. Increasing the salt concentration
of the silica sol at constant pH enhanced the deposition of the silica particles. Reducing the pH of the sol from 10 to 6
decreased the deposition rate due to aggregation of the primary silica particles. 相似文献
2.
Dominik L. Jürgen-Lohmann Christoph Nacke Raymond L. Legge Leonardo C. Simon 《Journal of Sol-Gel Science and Technology》2009,50(1):77-86
Sol–gels are seeing widespread interest as suitable materials for the immobilization of biomolecules in applications ranging
from optical coatings to specialty biocatalysts. Although there are numerous studies that have characterized these materials
in terms of their macroscopic properties, few studies have examined and correlated these properties at the microscopic level.
This study describes a spin-coating technique for the preparation of aluminum-supported sol–gel thin films containing immobilized
lysozyme [E.C. 3.2.1.17] that are suitable for chemical mapping using FTIR microscopy operating in reflectance mode. This
type of information can then be used to understand a variety of aspects of these materials which can be used for optimal engineering
of these materials, as well as insightful design and modeling. A data analysis method was developed to extract information
on chemical speciation and domain information on the materials from FTIR data matrices. Results from these studies indicated
that, contrary to what might be expected, these sol–gels are not homogeneous on the microscopic level. Instead, they are heterogeneous
in both the distribution of lysozyme and hydrophobic monomers at the scale investigated (20 μm resolution). The method described
here has promise in terms of providing a non-invasive approach of chemically mapping concentrations of proteinaceous and related
substances as well as chemical domains in situ in sol–gel thin films. 相似文献
3.
Idalia Bilecka Martin Kubli Esther Amstad Markus Niederberger 《Journal of Sol-Gel Science and Technology》2011,57(3):313-322
Combination of the surfactant-free nonaqueous sol–gel approach with the microwave technique makes it possible to synthesize
Fe3O4, CoFe2O4, MnFe2O4, and NiFe2O4 nanoparticles of about 5–6 nm and with high crystallinity and good morphological uniformity. The synthesis involves the reaction
of metal acetates or acetylacetonates as precursors with benzyl alcohol at 170 °C under microwave irradiation of 12 min. Immersion
of glass substrates in the reaction solution results in the deposition of homogeneous metal ferrite films whose thickness
can be adjusted through the precursor concentration. If preformed nickel nanoparticles are used as a type of curved substrate,
the ferrite nanoparticles coat the seeds and form core–shell structures. These results extend the microwave-assisted nonaqueous
sol–gel approach beyond the simple synthesis of nanoparticles to the preparation of thin films on flat or curved substrates. 相似文献
4.
Benjawan Chaichua Pattarapan Prasassarakich Sirilux Poompradub 《Journal of Sol-Gel Science and Technology》2009,52(2):219-227
The in situ silica filling of natural rubber (NR) was carried out via the sol–gel reaction using tetraethoxysilane. The effect
of the in situ silica content on the curing, mechanical, dynamic mechanical and thermal properties of the composite vulcanizate
materials was investigated in comparison to that with a commercial silica preparation. The Mooney viscosity of the in situ
silica filled NR vulcanizates showed a lower value compared with that of the commercial filled ones. The mechanical properties
of the in situ silica composite materials, i.e., the moduli and compression set, were improved compared with the commercial
silica filler NR vulcanizates. The reinforcement effect of in situ silica did not accord with the Smallwood equation but in
contrast was in good agreement with the Guth and Gold equation using a shape factor (f) which itself was in close agreement with estimates derived from independent TEM analysis. The pseudo-network structure of
the in situ silica was low, which resulted in a lower storage modulus at 25 °C. By filling NR with in situ silica, the thermal
properties of the composite vulcanized material were also improved, and well dispersed in situ silica particles within the
NR matrix were also observed. 相似文献
5.
Natchamon Watcharakul Sirilux Poompradub Pattarapan Prasassarakich 《Journal of Sol-Gel Science and Technology》2011,58(2):407-418
In situ silica reinforcement of natural rubber (NR) grafted with methyl methacrylate (MMA) (MMA-GNR) was achieved via the
sol–gel reaction of tetraethoxysilane (TEOS) by the use of solid rubber and latex solutions. Silica contents within the MMA-GNR
as high as 48 and 19 phr were obtained when using the solid rubber and latex solutions, respectively, under optimum conditions.
The conversion efficiency of TEOS to silica was close to 95%. The in situ formed silica MMA-GNR/NR composite vulcanizates
were prepared. MMA-GNR/NR composite vulcanizates reinforced with the in situ formed silica prepared by either method had similar
mechanical properties to each other, but a shorter cure time and higher mechanical properties than those reinforced with the
commercial silica at 9 phr. The TEM micrographs confirmed that the in situ formed silica particles were well dispersed within
the MMA-GNR/NR composite matrix, whilst the commercial silica particles showed a significant level of agglomeration and a
lower level of dispersion. 相似文献
6.
Junwen Lu Wei Wang Aiqing Zhang Fatang Tan Xueliang Qiao 《Journal of Sol-Gel Science and Technology》2012,63(3):495-500
Hybrid nanocomposite films of magnesium oxide (MgO) in fluorinated polyimide (PI) from 4, 4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 4, 4′-Diaminodiphenyl ether (ODA) have been successfully fabricated via an in situ sol–gel polymerization technique. The MgO content in hybrid films was varied from 0 to 5 wt%. The hybrid films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), ultraviolet–visible (UV–Vis) spectroscopy and thermal gravimetric analyses (TGA). The results of FTIR, XRD and FESEM showed that the MgO nanoparticles were well dispersed in the polymer matrix due to the coordination between the carbonyl group of polymers and Mg atom, and the as-prepared hybrid films exhibited excellent optical transparency in the visible region and good UV-shielding properties in the UV region. Although the thermal stability of the hybrid films is slight inferior to pure PI, it is still good for the practical application below the temperature of 300 °C. 相似文献
7.
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
8.
Shuxi Dai Yang Wang Dianbo Zhang Xiao Han Qing Shi Shujie Wang Zuliang Du 《Journal of Sol-Gel Science and Technology》2011,60(1):17-22
Surface-patterned ZnO thin films were fabricated by direct imprinting on ZnO sol and subsequent annealing process. The polymer-based
ZnO sols were deposited on various substrates for the nanoimprint lithography and converted to surface-patterned ZnO gel films
during the thermal curing nanoimprint process. Finally, crystalline ZnO films were obtained by subsequent annealing of the
patterned ZnO gel films. The optical characterization indicates that the surface patterning of ZnO thin films can lead to
an enhanced transmittance. Large-scale ZnO thin films with different patterns can be fabricated by various easy-made ordered
templates using this combination of sol–gel and nanoimprint lithography techniques. 相似文献
9.
S. Sönmezoğlu T. A. Termeli S. Akın İ. Askeroğlu 《Journal of Sol-Gel Science and Technology》2013,67(1):97-104
In this work, tellurium (Te) doped CdO nanoparticles thin films with different Te concentrations (1, 3, 5, 7 and 10 %) were prepared by sol–gel method. The effects of Te doping on the structural, morphological and optical properties of the CdO thin films were systematically studied. From X-ray diffraction spectra, it has seen that all of thin films were formed polycrystalline and cubic structure having (111), (200) and (311) orientations. The structure of CdO thin films with Te-dopant was formed the unstable CdTeO3 monoclinic structure crystal plane ( $ {\bar{\text{1}}\text{22}} $ 1 ¯ 22 ), however, the intensity of this unstable peak of the crystalline phase decreased with the increase of Te-doping ratio. The strain in the structure is also studied by using Williamson-Hall method. From FE-SEM images, it has seen that particles have homogeneously distributed and well hold onto the substrate surface. Additionally, grain size increases from 27 to 121 nm with the increase of Te-doping ratio. Optical results indicate that 1 % Te-doped CdO thin film has the maximum transmittance of about 87 %, and the values of optical energy band gap increases from 2.50 to 2.64 eV with the increase of Te-doping ratio. These results make Te-doped CdO thin films an attractive candidate for thin film material applications. 相似文献
10.
Po-Tsung Hsieh Ricky Wen-Kuei Chuang Chao-Qun Chang Chih-Ming Wang Shoou-Jinn Chang 《Journal of Sol-Gel Science and Technology》2011,58(1):42-47
Yttrium-doped ZnO gel was spin-coated on the SiO2/Si substrate. The as-prepared ZnO:Y (YZO) thin films then underwent a rapid thermal annealing (RTA) process conducted at
various temperatures. The structural and photoluminescence characteristics of the YZO films were discussed thereafter. Our
results indicated that the grain size of YZO thin films being treated with various annealing temperatures became smaller as
compared to the ones without being doped with yttrium. Furthermore, unlike other ZnO films, the grains of YZO thin films appeared
to separate from one another rather than aggregating together as both types of the films were annealed under the same environment.
The photoluminescence characteristic measured showed that the UV emission was the only radiation obtained. However, the UV
emission intensity of YZO thin film was much stronger than that of the ZnO thin film after annealing them with the same condition.
It was also found that the intensity increased with an increase in the annealing temperature, which was caused by the exciton
generated and the texture surface of the YZO thin film. 相似文献
11.
The selection of sol compositions, conditions of preparation and storage of gels are an important aspects for encapsulating
biomolecules in gel matrix for applications in biosensor. In the present investigation, fluorescence spectroscopic measurements
(emission and fluorescence lifetimes) were carried out in bulk gel and thin films prepared from sols with water and tetraethyl-orthosilicate
(TEOS) containing different fluorescent probes viz Hoechst 33258 (H258), Pyranine (Py), and 7-Azaindole (7-AI) in different
sols. Sols were prepared with addition of water, HCl and surfactant Triton X-100, and stored at room temperature (RT) and
low temperature (4 °C). The spectral characteristics have been compared for two different storage conditions as a function
of aging. The results of the present study clearly suggested that the internal environment of gels specifically the content
of water inside the pores of the sol–gel matrix can be controlled by storage at 4 °C as compared to RT. 相似文献
12.
A. Solieman 《Journal of Sol-Gel Science and Technology》2011,60(1):48-57
Sol gel derived indium oxide, In2O3; films were prepared by spin coating technique. The films were dried and sintered at different sintering temperatures (300,
400, 450 and 500 °C) in air. The effect of sintering temperature on the structural, optical and electrical properties of In2O3 thin films was studied. The morphology and structure of the films were analyzed by scanning electron microscope and X-ray
diffraction. The films showed a bcc structure that changes its 400-preferential orientation to 222 orientation as the sintering
temperature increases from 300 to 500 °C. The optical behavior of the films was studied by measuring the transmission spectra
in the wavelength range 200–2,500 nm. Different optical models have been proposed for fitting the transmittance data and simulate
the optical constants as well as the film thickness of In2O3 films. The best fitting of the data was obtained by combining the classical Drude and OJL models coupled with the Bruggeman
effective medium approximation. The optical parameters of Drude model (plasma frequency and damping constant) are used calculate
the electrical properties of the films. The calculated values of the electrical sheet resistance were compared with those
measured experimentally by four probes. The correlation between the film orientation change and its optical and electrical
properties was discussed. 相似文献
13.
Chenxi Zhang Wei Cao Adetayo V. Adedeji Hani E. Elsayed-Ali 《Journal of Sol-Gel Science and Technology》2014,69(2):320-324
Vanadium dioxide (VO2) thin films were fabricated using a simple and novel sol–gel process in which V2O5 was used as the vanadium source; oxalic acid was used as the reducing agent; and polyvinyl alcohol was used as the film former to control the viscosity of the VO2 precursor solution and bond vanadium ions. The microstructure and surface morphology of VO2 films were studied by X-ray diffraction and scanning electron microscopy, respectively. The results showed that using polyvinyl alcohol forms porous nanostructure of VO2 films with a uniform grain size of ~25 nm. The measured optical reflectance shows well-defined phase transition as observed by an increase of reflectance upon heating above the transition temperature from ~11 to ~30 % at 1,100 nm. Upon cooling, the expected hysteresis is observed. 相似文献
14.
Betul Akkopru Akgun Nathan P. Mellott Caner Durucan 《Journal of Sol-Gel Science and Technology》2012,62(2):240-251
Silver containing silica (Ag–SiO2) thin films with and without aluminum (Al) were prepared on soda-lime-silica glass by spin coating of aqueous sols. The coating
sol was formed through mixing tetraethyl orthosilicate [Si(OC2H5)4]/ethanol solution with aqueous silver nitrate (AgNO3) and aluminum nitrate nonahydrate [(AlNO3)3·9H2O] solutions. The deposited films were calcined in air at 100, 300 and 500 °C for 2 h and characterized using x-ray diffraction,
UV-visible and x-ray photoelectron spectroscopy. The effect of Al incorporation and calcination treatment on microstructure
and durability of the films, and chemical/physical state of silver in the silica thin film have been reported. The bactericidal
activity of the films was also determined against Staphylococcus aureus via disk diffusion assay studies before and after chemical durability tests. The investigations revealed that the optical,
bactericidal properties and chemical durability of Ag–SiO2 films can be improved by Al addition. The Al-modified Ag–SiO2 thin films do not exhibit any coloring after calcination in the range of 100–500 °C, illustrating that silver is incorporated
within the silica gel network in ionic form (Ag+). Al incorporation also improved the overall durability and antibacterial endurance of Ag–SiO2 thin films. 相似文献
15.
Journal of Sol-Gel Science and Technology - Electrocatalytic hydrogen evolution is an exercisable way to achieve large-scale application of hydrogen energy. It is of great significance to develop... 相似文献
16.
Cheng-Lan Lin Zhen-Wei Yang Chih-Hsien Chen 《Research on Chemical Intermediates》2017,43(6):3553-3562
Tungsten trixoide/titania (WO3-titania) composite thin films with W/Ti molar ratios of 100/0, 98/2, 96/4, 94/6 92/8 and 90/10 were prepared on fluorine-doped tin oxide conducting glass, and their electrochromic (EC) and photoelectrochromic (PEC) performances were investigated in this study. The composite thin films were synthesized by sol–gel process using peroxotungstic acid and titanium (IV) n-butoxide as the precursors. The surface morphology and composition of the composite thin films were characterized using scanning electron microscope with energy dispersive spectrometer. Electrochemical experiments with in situ spectroscopic measurement were employed to study the EC properties of the composite thin films. It was found that the presence of titania in the WO3 matrix might slightly decreases its EC performance. PEC cells using the composite thin films as the working electrode and a sputtered semitransparent platinum thin film on ITO as the counter electrode were fabricated and their PEC performances were investigated. The device using composite thin film prepared from sol solution with a W/Ti molar ratio of 96/4 exhibited the best PEC performance. 相似文献
17.
A. Mehner J. Dong T. Prenzel W. Datchary D. A. Lucca 《Journal of Sol-Gel Science and Technology》2010,54(3):355-362
Sol–gel silica hybrid coatings from acid and base catalyzed sols were examined. The sol precursors were tetraethyl orthosilicate (TEOS) and methyltriethoxysilane (MTES). It is generally accepted that the type of catalyst has a significant impact on the micro-structure of the resulting polysilicates. Weakly branched polymers are formed in acid catalyzed sols and highly branched, compact, particle like polymers are formed in base catalyzed sols. The mechanical and chemical properties of sol–gel derived silica coatings from acid and base catalyzed sols were studied as a function of the heat treatment temperature and time. Hardness and elastic modulus were measured by micro indentation measurements. The chemical composition of both types of coatings was characterized by X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR). 相似文献
18.
Keh-moh Lin Yu-Yu Chen Chiao-yuan Chiu 《Journal of Sol-Gel Science and Technology》2010,55(3):299-305
In this study, we investigated the effects of different heating processes on the structural, electrical and chemical properties
of ZnO:Ga (GZO) films from the viewpoint of nucleation and growth behaviors. An infrared heating furnace and a traditional
tube furnace were employed for the homogeneous and heterogeneous nucleation of GZO films. XRD patterns demonstrated that the
preferential growth orientation of both kinds of GZO films is still the (002) direction. XPS data implied that the infrared
heating process enables more uniform distribution of the dopant material and retards the oxidization of gallium in grain boundary
areas. At the same time, the textured crystallite might provide a free tunnel for oxygen diffusion. Thus, the activation of
free charge carriers could be more efficient when the GZO films were annealed under vacuum. As a result, the samples annealed
by the infrared heating furnace had a noticeably high carrier concentration. Although the mobility was slightly smaller than
that of the samples annealed by the tube furnace, film resistivity dropped obviously in general. 相似文献
19.
G. J. A. A. Soler-Illia P. C. Angelomé M. C. Fuertes A. Calvo A. Wolosiuk A. Zelcer M. G. Bellino E. D. Martínez 《Journal of Sol-Gel Science and Technology》2011,57(3):299-312
Mesoporous Thin Films (MTF) can be created by combining sol–gel synthesis, template self-assembly and chemical surface modification.
A wide palette of inorganic (oxides, phosphates, carbon-based, etc.) and hybrid organic–inorganic frameworks with a variety
of composition, pore sizes, and nanoscale, organic or biological functions located in the inorganic skeleton, pore surface
or pore interior can be obtained. The properties of the functional pore systems are tuned by the pore size and geometry, wall
composition and surface features. These MTF with interesting electronic and optical controlled features are indeed a “nanofacility”. Well-defined monodisperse sized pores also act as nanoreactors, or nanocavities with controlled environment and behaviour.
In the last years, the production of accessible MTF, in which either the pore surface or pore volume can be modified by organic
functional groups or nanoparticles has been thoroughly explored. Each highly controlled MTF originated from a reproducible
and modular synthesis is in itself a building block for more complex structures, presenting order at different length scales (molecular, mesoscopic, macroscopic), and novel properties derived thereof.
Selected examples of optical and chemical behaviour of these multiscale materials are presented to illustrate these points. 相似文献
20.
K. Thongsuriwong P. Amornpitoksuk S. Suwanboon 《Journal of Sol-Gel Science and Technology》2012,62(3):304-312
Silver-doped ZnO thin films with various loadings of Ag in the range of 0–10 mol% were prepared by the sol–gel dip-coating
method. All prepared films show X-ray powder diffraction patterns that matched with ZnO in its würtzite structure. The grain
size decreased as the Ag loading increased. The prepared films, under UV blacklight illumination, produced a photocatalytic
degradation of methylene blue, rhodamine B and reactive orange solutions. Furthermore, they inhibited the growth of Escherichia
coli bacteria under UV blacklight irradiation and to a lesser extent in dark conditions. The photocatalytic and antibacterial
activities of the prepared films increased with Ag loading, presumably because Ag enhanced the efficiency of generation of
superoxide anion radicals (•O2
−) and hydroxyl radicals (•OH). 相似文献