共查询到20条相似文献,搜索用时 15 毫秒
1.
Ling Zhou Yanyue Kong Shian Zhong Xiaorun Zhou 《Journal of Sol-Gel Science and Technology》2013,66(1):59-67
This work adopted semi-covalent imprinting to prepare molecularly imprinted polymers (MIP) with ibuprofen, a non-steroidal anti-inflammatory drug, as template by sol–gel processing, which is characterized by both the high affinity of covalent binding and the mild operation conditions of non-covalent rebinding. A functional monomer, which was used to synthesize the monomer-imprinted molecule complex, was prepared by multi-step synthesis for the first time. MIP was characterized by Fourier transform IR spectrum and nitrogen adsorption. Thin-layer chromatography separation was used to evaluate the specific molecular recognition ability of MIP. In addition, dynamic and thermodynamic studies on MIP imprinting ibuprofen were undertaken. The results of equilibrium rebinding experiments showed that MIP exhibited good adsorption capacity for ibuprofen. Scatchard analysis illustrated that the template-polymer system shows only one-site binding behavior with a dissociation constant of 1.84 mmol L?1. Dynamic adsorption exhibited pseudo-second-order kinetics. The positive value of ΔHθ and the negative values of ΔGθ demonstrated that the binding system for MIP is endothermic and spontaneous. 相似文献
2.
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
3.
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
4.
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
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
6.
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
7.
The sol–gel-derived host matrices are well known for biosensor applications where various types of organic and biological
molecules can be immobilized and can act as recognition elements. The molecular imprinting technology is an attractive alternative
method where expensive and labile biorecognition elements can be replaced by molecular imprinted polymers (MIPs), which are
capable of recognizing a target molecule of an interest. In the present study, hybrid sol–gel MIPs were synthesized in the
form of crushed powder (CP) by both non-hydrolytic and hydrolytic method for cholesterol recognition. These MIPs were characterized
by scanning electron microscopy (SEM), fourier transform-infrared (FT-IR), liquid chromatography-mass spectrometry (LC–MS)
and nitrogen adsorption–desorption isotherm measurements. The template molecule was extracted by means of soxhlet extraction
and calcination method. The cholesterol adsorption experiments were performed by using non-imprinted (NI) and extracted crushed
powder (ExCP) and the percentage of adsorption was determined by measuring the residual quantity in the analyte solution using
Liebermann-Burchard (L-B) reagent. The adsorption studies with non-imprinted crushed powder (NICP) showed interference with
L-B reagent as well as non-specific binding between analyte molecules and silica matrix. The percentage of adsorption or rebinding
was found to be higher for phenyl triethoxysilane (PhTEOS)-derived ExCP (composition 3) which was synthesized by the aqueous
sol–gel processing method at low pH as compared to PhTEOS-derived (composition 1) and 3-aminopropyltriethoxysilane (APTES)-derived
ExCP (composition 2) prepared by non-hydrolytic method. The reusability of used ExCP after re-extraction was also investigated.
The various factors affecting rebinding of template molecules were discussed along with interference study. The study provided
information on molecular imprinting of cholesterol in sol–gel matrix and highlighted the importance of characterization of
MIPs before applying it for sensing applications. 相似文献
8.
Daniel Membreno Leland Smith Bruce Dunn 《Journal of Sol-Gel Science and Technology》2014,70(2):203-215
There is widespread recognition that the use of energy in the twenty-first century must be sustainable. Because of its extraordinary flexibility, silica sol–gel chemistry offers the opportunity to create the novel materials and architectures which can lead to significant advances in renewable energy and energy storage technologies. In this paper, we review some of the significant contributions of silica sol–gel chemistry to these fields with particular emphasis on electrolytes and separators where sol–gel approaches to functionalization and encapsulation have been of central importance. Examples are presented in the areas of dye-sensitized solar cells, biofuel cells, proton exchange membrane fuel cells, redox flow batteries and electrochemical energy storage. Original work is also included for the sol–gel encapsulation of a room temperature ionic liquid to create a solid state electrolyte for electrochemical capacitors. In view of the critical importance of energy and the versatility of the sol–gel process, we expect the sol–gel field to play an increasingly important role in the development of sustainable energy generation and storage technologies. 相似文献
9.
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
10.
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
11.
Noncrystalline and nanocomposite materials of (1?x)SiO2·xGeO2 system, with Si:Ge ratio from 8:1 to 2:1 (x?=?0.111; 0.142; 0.2; 0.333), initially obtained by sol?Cgel method, were characterized by thermal analyses, X-ray diffraction, nuclear magnetic resonance and Raman spectroscopy. According to DTA and XRD results, the noncrystalline state of the as-prepared samples is stable up to 1,000?°C and only after 30?min heat treatment at 1,200?°C the samples become partial crystalline, due to development of cristobalite and quartz nanocrystals. Solid-state 29Si MAS-NMR was employed in order to characterize the local structure around silicon as a function of composition and thermal history of the samples. The NMR data indicate the presence of Q2, Q3 and Q4 units in all samples. The fraction of the highly interconnected SiO4 tetrahedra increases both with germanium content and with annealing temperature. The Raman spectroscopy results evidence structural changes related to silicon- and germanium-oxygen units but also to their interconnection, that depend on Si:Ge ratio and annealing temperature. 相似文献
12.
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
13.
L. Guardia R. Badía M. Granda-Valdés M. E. Díaz-García 《Journal of Sol-Gel Science and Technology》2012,63(3):537-545
Properties of tailored imprinted sol–gels are extremely dependent on the synthesis conditions and on the nature of the reagents used due to the diversity of combinatory interactions among the sol–gel components and the large number of chemical requirements for the sol–gel process. In this paper, methyltrimethyl orthosilicate was used as precursor to create molecularly imprinted polymers against the β-lactamic antibiotic nafcillin under different experimental conditions. A 22 member–library of imprinted sol–gels against nafcillin, and the respective control materials, was produced. Screening of the library members was performed by room temperature phosphorescence (RTP) flow-injection analysis and by batch RTP re-binding assays. A 22 factorial experimental design was also performed in selected sub-libraries of imprinted sol–gels as a function of the template and the additive concentrations, both using acid and basic catalysis. 相似文献
14.
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
15.
16.
Torsten Brezesinski John Wang Sarah H. Tolbert Bruce Dunn 《Journal of Sol-Gel Science and Technology》2011,57(3):330-335
Capacitive energy storage is distinguished from other types of electrochemical energy storage by short charging times and
the ability to deliver significantly more power than batteries. A key limitation to this technology is its low energy density
and for this reason there is considerable interest in exploring pseudocapacitive charge storage mechanisms which offer the
prospect of increasing energy density without compromising the power density of electrochemical capacitors. In this paper
we review our recent work on using sol–gel synthesis methods to prepare nanostructured transition metal oxides which exhibit
increased levels of pseudocapacitance and enhanced energy storage properties. Our work with TiO2 nanoparticles and mesoporous films of TiO2 and CeO2 is highlighted as we use these studies to understand the role of crystallite size, nanoscale porosity and understanding the
differences between pseudocapacitance and intercalation processes. 相似文献
17.
X. Zhang M. Qian X. Zeng Z. Zhao J. Lasante P. Plante 《Journal of Sol-Gel Science and Technology》2008,45(1):103-107
Multi-layer buried rib waveguides were fabricated using sol–gel derived photopatternable organic–inorganic hybrid materials
through multi-step spin coating and photolithography. A single mode circular waveguide at 1,550 nm was designed and fabricated
using the equivalent refractive index method. Propagation loss in the order of 1.0 dB/cm was measured by cutback method. Waveguide
thermal stability and thermo-optic coefficient were investigated using thermogravimetric analysis (TGA) and spectroscopic
ellipsometry, respectively. Results suggest that the single mode waveguide can be used to develop thermal optical devices
such as thermo-optic switches. 相似文献
18.
V. Senthilkumar P. Vickraman R. Ravikumar 《Journal of Sol-Gel Science and Technology》2010,53(2):316-321
This article presents novel attempt to synthesis of fluorine doped tin oxide (FTO) nanoparticles by sol–gel technique. The
synthesized FTO nanoparticles were obtained after calcination. Temperatures of calcination were 600 and 700 °C due to identify
changes in the particles size growth. A DG/DTA and FTIR study identifies the oxide and formation of the nanopowders. The XRD
studies confirm the tetragonal crystallite structure of fluorine doped tin oxide. The TEM image confirms the size of FTO particles
in nanoscale. The electrical studies on FTO nanopowders results the decrease in resistivity profile with increasing calcinations.
The optical band gap studies for sol–gel synthesis FTO nanoparticles is found to be in the range of 4.11–3.84 eV conforming
decreasing optical band gap with increasing calcinating temperatures. 相似文献
19.