共查询到20条相似文献,搜索用时 15 毫秒
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The manufacturing of ophthalmic lenses is one of the most important markets worldwide and, therefore, strong research efforts are undertaken to continuously improve the quality of the products, either silicate glasses or organic polymer lenses. Hybrid sol-gel based materials play a major role in this highly competitive field and have contributed significantly to the commercial success of the organic base materials. Recent developments concern fast curing and patternable coatings that might soon become part of this business. The compatibility of hybrid sol-gel materials either with organic dyes or with inorganic vacuum borne coatings offers further possibilities to develop highly sophisticated lenses meeting not only customer needs like perfect corrective function, high optical quality and protection, but also high durability as well as cosmetic and decorative aspects. An overview and a few recent developments are outlined below. 相似文献
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讨论了溶胶 -凝胶法合成有机 /无机杂化聚合物材料中的增容剂的应用 ,并详细介绍了三类增容剂的结构、增容机理和性能。 相似文献
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Rohan L. Holmes Jonathan A. Campbell Robert P. Burford 《Polymer Degradation and Stability》2009,94(10):1882-1889
Inorganic-organic hybrid materials are studied due to the unique properties they exhibit. As these materials become more widely applied, particularly as precursor materials for forming inorganic materials, it is essential that the pyrolysis behaviour is understood. Transparent yellow hybrid materials consisting of titanium dioxide and poly(vinyl pyrrolidone) were prepared using sol-gel processing techniques. The hybrids maintained their transparency up to the highest achieved inorganic loading of 57 wt.%. These materials were characterised using thermogravimetric analysis in which the organic component was pyrolysed. The resultant chars were then investigated using optical microscopy, x-ray diffraction, scanning electron microscopy, and atomic force microscopy. The inorganic loading had an effect on char formation, with higher loadings leading to the formation of pyrolysis intermediates which were less apparent in samples of lower inorganic content. The pyrolysis intermediates were found to be carbon-rich. 相似文献
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Jaime Retuert Alicia Nuez Francisco Martínez Mehrdad Yazdani-Pedram 《Macromolecular rapid communications》1997,18(2):163-167
This work reports the synthesis of a novel polymeric organic-inorganic hybrid. The inorganic component is a silica network obtained by controlled hydrolysis of tetraethyl orthosilicate via sol-gel process and the organic counterpart is partially deacetylated chitin (CHI). The resulting polymer hybrids were homogeneous transparent film forming glassy materials being compatible through a wide composition range. Simultaneous thermal analysis of a CHI/silica 1:1 mixture confirms the intermolecular complex formation between organic and inorganic polymers. 相似文献
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Optical Chemical Sensors Based on Sol-Gel Materials: Recent Advances and Critical Issues 总被引:1,自引:0,他引:1
B.D. Mac Craith C. Mc Donagh A.K. McEvoy T. Butler G. O'Keeffe V. Murphy 《Journal of Sol-Gel Science and Technology》1997,8(1-3):1053-1061
The use of the sol-gel process to produce materials for optical chemical sensors and biosensors is attracting considerable
interest. This interest derives mainly from the design flexibility of the sol-gel process and the ease of fabrication. In
most applications the sol-gel material is used to provide a microporous support matrix in which analyte-sensitive species
are entrapped and into which smaller analyte molecules may diffuse. Sensors based on entrapped organic and inorganic dyes,
enzymes and other biomolecules have been reported. A range of sensor configurations has been employed, including monoliths,
thin films, as well as more elaborate structures. In this paper a selection is presented of recent significant developments
in optical chemical sensors which employ solgel-derived materials. These developments include the tailoring of sol-gel materials
to optimise sensor response, advanced waveguide structures and novel probe-tip sensors. Those issues which remain critical
to the eventual deployment of sol-gel sensors are examined. In particular, the problems of leaching, microstructural stability,
diffusion-limited response time, and susceptibility to interferents are discussed and some solutions proposed. 相似文献
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Jinliang Liu 《Journal of organometallic chemistry》2010,695(4):580-587
This work focuses on the construction of a series of chemically bonded rare-earth/inorganic/organic hybrid materials (TCH-Si-Ln, TCH-Si-Ln-Phen and TCH-Si-Ln-Bipy: Phen = 1,10-phenanthroline, Bipy = 2,2′-bipyridyl) using TCH-Si as an organic bridge molecule that can both coordinate to rare-earth ions (Eu3+ and Tb3+) and form an inorganic Si-O-Si network with tetraethoxysilane (TEOS) after cohydrolysis and copolycondensation through a sol-gel process. All of these hybrid materials exhibit homogeneous microstructures and morphologies, suggesting the occurrence of self-assembly of the inorganic network and organic chain. Measurements of the photoluminescent properties of these materials show that the ternary europium systems present stronger luminescent intensities than the binary hybrids, indicating that the introduction of the second ligands can sensitize the luminescence emission of the europium hybrid systems. However, in the terbium systems, this phenomenon was not observed. 相似文献
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Po-I Lee 《European Polymer Journal》2007,43(2):294-299
A novel organic/inorganic hybrid material has been prepared through the sol-gel process. A high temperature polymer, polybenzoxazole (PBO), was chosen as the organic phase due to its inherent low dielectric constant and low water absorption. The inorganic phase was generated via sol-gel reaction from a silica precursor, phenyltriethoxysilane (PTEOS). Due to the hydroxyl groups in the PBO precursor backbone and the water release during the cyclization of the precursor, the sol-gel reaction proceeded without the addition of water and any catalyst. After curing at 350 °C, we obtained the PBO/silica nanocomposites. From TEM and SEM photographs, the silica particles dispersed in the PBO matrix were nano-sized. With an addition of 100 wt% of PTEOS, the Tg of PBO was increased 35 °C. The dielectric constant of the hybrid materials increased with the increasing amount of PTEOS. 相似文献
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The family of fullerene molecules is composed of a large variety of compounds that have been synthesized following the discovery of C60 in 1985. The chemistry of fullerenes, developed in these last years, has allowed designing the properties of this family of molecules for specific applications in materials science. One of the main tasks to build up solid state devices based on fullerenes is the synthesis of materials doped with a highly dispersed and homogeneous distribution of fullerenes. Many of the peculiar photophysical properties, such as the reverse saturable absorption used to obtain a solid state optical limiter, are in fact lost in the aggregates of fullerenes. Sol-gel processing allows preparing inorganic oxides and hybrid organic-inorganic materials at low temperatures and presents an interesting alternative to organic polymers to entrap molecules of the fullerene family in a solid matrix. Porous inorganic solids and aerogels are also important classes of materials that can be synthesized via sol-gel and can act as hosts of fullerenes. In the present article we have reviewed the main achievements of sol-gel processing of fullerene based nanocomposite materials. 相似文献
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Signorini Raffaella Meneghetti Moreno Bozio Renato Brusatin Giovanna Innocenzi Plinio Guglielmi Massimo Negra Federico Della 《Journal of Sol-Gel Science and Technology》2001,22(3):245-253
Hybrid organic-inorganic materials are investigated as suitable materials for inclusion of fullerene derivatives and for fabrication of laser protection devices. A specific synthesis has been developed in order to optimize non-linear optical performances of fullerene derivatives. 3-glicydoxypropyltrymethoxysilane has been used as an inorganic and organic network former to obtain the host material. The sol-gel synthesis consists of the hydrolysis and condensation in acidic conditions of the inorganic network. Epoxy polymerization has been achieved by using zirconium or BF3 alkoxides precursors. Bulk and multilayer materials doped with a fullerene derivative have been fabricated. They show good optical requirements: high fullerenes concentration, high microstructural homogeneity, high laser damage threshold and high optical limiting efficiency. Optical limiting (OL) mechanisms have been investigated. The most effective in the sol-gel materials is the reverse saturable absorption (RSA) one. However, different mechanisms, like non-linear (NL) scattering and NL refraction contribute to a different extent. Open- and closed-aperture OL and z-scan measurements on sol-gel samples show the contribution of NL scattering and NL refraction at 690 nm. Laser damage threshold has been characterized as a function of the structure of the samples and of the optical configurations (f/66 and f/5). 相似文献
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A new type of thermo-responsive hydrogels based on the polymer poly(N-isopropyl acrylamide) (PNIPAA) has been synthesized with the sol-gel technology. For the preparation of this type of nano-structured hydrogels, the inorganic silica phase was synthesized by the sol-gel process in the presence of an aqueous solution of high molecular weight PNIPAA. This combination of the organic and inorganic phases forms hybrid hydrogels with a semi-IPN morphology. The unique structure of these hydrogels improves the mechanical stability to a great extent as compared to conventional PNIPAA-hydrogels. This was shown by stress-strain experiments and the capability to absorb and desorb large amounts of water. The silica only slightly influences the transition temperature of the hydrogels but allows us to vary the thermo-responsive properties of the materials to a great extent. 相似文献
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Ormosils are well-known organic-inorganic sol-gel derived materials also called heteropolysiloxanes. This paper presents two basic heteropolysiloxane structures where the organic part is either a short organic chain bridging two silicon atoms for the first material or an organic polymer backbone for the second. Their synthesis is detailed and a variety of experimental techniques (IR, 13C and 29Si NMR and CP-MAS NMR, GPC) have been employed to investigate the chemical structure of these new materials. Their mechanical properties, more precisely their viscoelastic behaviour, have been evaluated using dynamic rheological techniques. The storage and loss moduli have been followed during the sol-gel transition at fixed and variable oscillation frequencies. The results have been correlated to the 29Si CP-MAS NMR informations concerning the network polycondensation and compared to a pure inorganic sol-gel material prepared from tetraethoxysilane. 相似文献
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Sol-gel process has gained tremendous attention in past decades for the preparation of pure and composite material for numerous
applications. Organically modified sol-gel glasses (ormosils) have hybrid properties of rigid inorganic silica matrix and
organic functionalities. Ormosils provide ambient environment for bio-molecules encapsulation and such systems have been used
widely for biosensor applications. Biological elements including enzymes, antibodies, antigens, DNA, whole cells, tissues,
proteins, biologically derived material, and biomimetic materials provide the possibility of biological recognition to the
device and transducer to detect the biological signals with the help of associated electronics and software to amplify these
signals into a readable form for the user. In this review we report on the formation of sol-gel based composite materials
primarily on ormosil along with carbon nano tubes, metal nano particles, mediators, inorganic complexes, polymers, ionomers
and biological materials and cite the electrochemical sensor/biosensor system based on it. 相似文献
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Ahmed Salama 《Journal of carbohydrate chemistry》2016,35(3):131-149
Polysaccharides/silica hybrids prepared through sol-gel reaction have been studied as a model for new generation of hybrid materials for a virtually unlimited number of applications. Numerous studies have therefore attempted to increase the homogeneity between the organic and inorganic moieties using a wide variety of silica precursors and crosslinking reagents. The current review summarizes and discusses the attempts for using polysaccharides for producing hybrid materials with collective properties from the two counterparts. It discusses several issues and strategies to tune the homogeneity of polysaccharide/silica hybrids and the potential applicability of these hybrid materials in biomedical and industrial fields. 相似文献
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A fast convenient method to prepare hybrid sol-gel materials with low volume-shrinkages 总被引:1,自引:0,他引:1
Yen Wei Danliang Jin Chuncai Yang Gu Wei 《Journal of Sol-Gel Science and Technology》1996,7(3):191-201
We present a simple and fast method for the synthesis of polyacrylates-silica hybrid materials with significantly low volume shrinkages through the sol-gel reactions of tetraethyl orthosilicate and 2-hydroxyethyl methacrylate along with the free-radical polymerization of the acrylate monomer. The volume shrinkage from the processible sol to the final product was about 6–20% for the hybrid materials having the silica contents up to about 50 wt-%. As a result of the low shrinkage, crack-free, transparent and monolithic hybrid materials of relatively large sizes can be prepared within a short period of 6 to 12 hours. The formation of covalent bonding between the organic and the silica components in the hybrid materials was demonstrated. Thermal stability of the polyacrylate component in the hybrid materials were found to be higher than that of the bulk polymer. Other vinyl polymers such as poly(methyl methacrylate) and polyacrylonitrile have also been incorporated into the inorganic silica sol-gel matrix by using this method. 相似文献
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The incorporation of organic dyes into inorganic and hybrid sol-gel derived materials is a valuable method for the fabrication of colored layers for optical applications like filters, solar energy conversion, non-linear optical devices, and active laser media. There have been clear hints for photochemical stabilization of the organic dyes, therefore, our aim was to investigate the light stability of organic dyes within hybrid solids. Besides the traditional way of doping sol-gel coatings with dyestuffs, they were also covalently attached to the hybrid matrix and pigments were produced by spray-drying processes.The resulting spherical powders were investigated with respect to their morphological, structural and photochemical properties. The results show that uniformly shaped and colored hybrid pigments can be synthesized. The spectroscopic studies demonstrate the fixation of the dye to the matrix and the high degree of crosslinking achieved in the composite. Additionally, the hybrid pigments drastically improve the resistance of the dye against bleeding from thermoplastic polymers. Furthermore, a higher photochemical stability of the dye is observed within the hybrid matrix compared to a solution, and purely organic or inorganic solid hosts. 相似文献
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Poly(ε-caprolactone-b-perfluoropolyether-b-ε-caprolactone) (PCL-PFPE-PCL) triblock copolymers having hydroxy end groups were readily functionalised with triethoxysilane end groups by reactions with 3-isocyanatopropyltriethoxysilane. Organic-inorganic hybrids were prepared by using the sol-gel process in the presence of tetraethoxysilane and hydroxy or triethoxysilane terminated PCL-PFPE-PCL. Fully transparent hybrid materials with high content of organic matter were obtained only in the case of alkoxysilane functionalised copolymers. For such systems the PCL-PFPE-PCL copolymer was so intimately mixed with the inorganic network to prevent crystallisation of the PCL segments. The progress of the sol-gel reaction was limited by the early vetrification of the reactive system, while the interpenetration of the organic phase was enhanced by curing the samples at 100 °C. 相似文献
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溶胶-凝胶法合成聚甲基丙烯酸甲酯/二氧化钛杂化聚合物材料 总被引:7,自引:0,他引:7
由共聚合在PMMA聚合物链段上引入了-Si(OR)3功能团,通过溶胶-凝胶过程合成了PMMA/TiO2杂化聚合物材料.溶剂抽提结果表明有化学键存在的杂化材料体系中凝胶的含量很高.通过FTIR测试对材料结构进行了分析,由TGA、DSC测试分析了杂化材料体系中无机组份的含量对材料性能的影响. 相似文献