Sol-Gel Preparation of Ceramic Coatings for Electrical, Laser, Space Engineering and Power

The brief review, based on long-term experience of authors on preparation of temperature-resistant electric insulating and optical light-reflecting ceramic coatings on metal surface is offered. The main components of TEOS-, H₃PO₄- and alkali silicates-derived sols and suspensions for deposition of ceramic coatings are listed. Some features of preparation of the coatings from the sols containing fillers are analysed. Two approaches to improve bending and electrical strength of flexible insulation are developed. The techniques of synthesis of modified fillers for preparing gas-proof and anticorrosive coatings are offered. The wide functional possibility and extensive list of application areas of the coatings and some materials prepared from sols with fillers, including on far prospect are given.     

Hybrid Organic-Inorganic Sol-Gel Materials Based on Epoxy-Amine Systems

Understanding the synthesis-structure-properties relationship of hybrid organic-inorganic materials is an important and fundamental task to develop a new generation of highly performing systems for the new needs of nanotechnologies. This issue is, also, important to improve the properties of hybrids when used in applications where nanoscale control is not a fundamental request. In this article, a short overview of epoxy amine sol-gel hybrids is reported. The synthesis of these materials has a large flexibility to allow the fabrication of a wide group of hybrids with different structures and properties, whose applications are ranging from non-linear optics to adhesive and protective coatings.     

Adhesion of Sol-Gel-Derived Organic-Inorganic Hybrid Coatings on Polyester

Inorganic coatings, including metal-oxide coatings, provide polymer surfaces with excellent abrasion and wear resistance, and protection against environmental degradation. However, one drawback associated with the incorporation of such ceramic coatings to polymeric materials is the adhesion characteristic at the ceramic-polymer interface. In this paper, two strategies for adhesion enhancement of ceramic coatings on polymer substrates were proposed: (1) formation of chemical bonds through surface condensation reactions, and (2) development of interlocked ceramic and polymeric networks through diffusion of alkoxide precursors. The current research has focused on the adhesion of sol-gel-derived organic-inorganic hybrid coatings on polyester by forming chemical bonds between the polymer substrate and the hybrid coatings, as well as developing interlocked polymeric and inorganic networks at the interface. Contact angle, wettability tests, and chemicalanalysis were done to verify the effectiveness of the adhesion of organic-inorganic hybrid coatings on polyester substrates. In addition, dry and wet thermal cycling tests were done to analyze the adhesion behavior of the hybrid coatings on polyester, followed by microscopy examination. It was found that although both approaches resulted in excellent adhesion of hybrid coatings on polyester, adhesion with interlocked ceramic and polymeric networks was far better than that with chemical bonds in the presence of water at elevated temperatures.     

Sol-Gel Processing of Organic-Inorganic Nanocomposite Protective Coatings

Organic-inorganic nanocomposite protective coatings are prepared on aluminum substrates by the spinning technique with the concept of incorporating homogeneously nanosized particles (of AlOOH, Al2O3, ZrO2, SiC) into molecular organic-inorganic hybrid matrices. The hybrid matrices are prepared from epoxysilane and bisphenol A with imidazol as catalyst. The AlOOH particles are derived from aluminum isoprooxide and introduced into the hybrid sols directly, and Al2O3, ZrO2, SiC particles are first surface-modified with Si–OH from hydrolyzed TEOS. The coatings are dense, smooth and flexible and inhibit corrosion.     

Structural Analysis and Properties of Organic-Inorganic Hybrid Ionic Conductor Prepared by Sol-Gel Process

Organic-inorganic hybrid lithium ion conductors were prepared by the sol-gel process. The hybrid ion conductor will be used as the electrolyte for Li based high-energy density batteries. The hybrid ion conductor was prepared from a mixture of tetramethyl orthosilicate (TMOS), polyethylene glycol 200 (PEG₂₀₀), lithium perchlorate (LiClO₄) and water. A wet gel was prepared at room temperature. The gels dried at 80°C under vacuum did not contain water. The dried hybrid ion conductor gel had homogeneity and high transparency. Ionic conductivity of the hybrid sample was measured by the complex impedance method and it increased with increasing PEG₂₀₀ content. The dried hybrid gel that contained no LiClO₄ did not show ion conduction. Conductivity on the order of 10^–5 S·cm^–1 at room temperature was obtained. Structural characterization was done by Fourier Transform Infrared Spectra (FTIR) and NMR measurement of ¹³C and ¹H, and the thermal stability and glass transition properties were studied by DSC. Glass transition temperature decreased with increasing PEG₂₀₀ content and increased with increasing [Li]/[O] ratio (the oxygen considered is from the polyethylene glycol). Existence of the Si–O–(C₂H₄O) _n –bond and the C–OH bond in the framework of the organic and inorganic phases was confirmed. TMOS and PEG₂₀₀ were hydrolyzed and condensed. The organic and inorganic phases were chemically bonded and the microstructure of the hybrid matrix was shaped as comb. The comb shape leads to high ionic conduction.     

Sol-Gel Synthesis of Hybrid Organic-Inorganic Monoliths Doped with Colloidal CdSe/ZnS Core-Shell Nanocrystals

Colloidal CdSe/ZnS core-shell nanocrystals, with a narrow size distribution, were dispersed in a hybrid sol resulting from the hydrolysis of tetraethylorthosilicate and 3-glycidoxypropyltrimethoxysilane (GLYMO). In order to reduce the gelation time and the exposure of the nanoparticles to air, several catalysts of the GLYMO epoxy ring opening were employed for the sol preparation, such as imidazole, methyl-imidazole, pyridine, benzylamine, propylamine. The role of the various catalysts was monitored by optical absorption measurements in the near infrared region, by observing the evolution of the epoxy bands. Imidazole was found to provide the fastest gelation and the best results in terms of bubble disappearance from the gel structure. The variation in the optical properties of the semiconductor nanoparticles embedded in the matrix was monitored as a function of the gelation time and was compared to the optical absorption and photoluminescence spectra of the nanoparticles dissolved in a chloroform solution. A decrease in the gelation-time results in a closer resemblance between the optical properties of the CdSe/ZnS doped monoliths and those of the particles dissolved in the solvent, before incorporation in the matrix. The photoluminescence of the CdSe/ZnS nanocrystals is not bleached after they are trapped in the glassy matrix.     

Sol-Gel-Derived Hybrid Coatings for Corrosion Protection

The corrosion resistance of sol-gel-derived, organic-inorganic, silica-based hybrid coatings was studied. Hybrid sols were prepared by copolymerizing tetraethylorthosilicate (TEOS) and 3-methacryloxypropyltrimethoxysilane (MPS) with a two-step acid-catalyst process. Hybrid coatings were dip-coated on 304 and 316 stainless steel substrates and annealed at 300°C for 30 minutes. The adhesion, flexibility, and biocompatibility of the coatings were examined. Hybrid coatings were found to be relatively dense, uniform and defect free. Electrochemical analyses showed that the coatings provided excellent corrosion protection by forming a physical barrier, which effectively separated the anode from the cathode. In addition, further experimental results revealed that the corrosion patterns are strongly dependent on the nature of the stainless steel substrates. Some possible mechanisms for corrosion breakdown associated with each type of substrate are also introduced.     

PVB掺杂有机无机复合SiO2增透膜的制备和表征

以聚乙烯醇缩丁醛(PVB)为有机掺杂剂,正硅酸乙酯为前驱体,氨水为催化剂,利用溶胶-凝胶法制备出了一种新型的有机无机复合二氧化硅增透膜。采用红外光谱、X射线衍射、粒度分析、紫外分光光度法、椭偏测定、原子力显微镜、静滴接触角测量等对膜层性质进行了表征。结果表明：PVB分子的引入并没有引起增透膜结构的变化。在相同的实验条件下,未经PVB掺杂的SiO₂增透膜在720 nm处的峰值透过率为99.8％,而PVB掺杂后的SiO₂复合膜在840 nm处的峰值透过率在99.9%以上。掺杂膜层变厚,峰值透过率朝长波方向移动。掺杂前后增透膜对水的接触角从29°增加到71°,膜层的疏水性得到明显提高。     

溶胶-凝胶法制备有机/无机杂化材料工艺及其应用

介绍了溶胶–凝胶法制备有机/无机杂化材料的原理和基本过程,杂化材料的制备方法及对材料性能的影响,概述了杂化材料在结构材料、光学材料及其它材料中的应用研究。     

Sol-Gel Coatings on Metals

Sol-gel derived films can be deposited on metals to improve their resistance to oxidation and corrosion or to modify their surface properties. However, practical applications are limited by problems intrinsic to sol-gel processing or specific of coating/metal systems. Coatings aimed to improve oxidation and wet corrosion resistance have been the most studied. The results published in the literature show that sol-gel coatings may offer good protection against oxidation. More difficult is to achieve a protection against wet corrosion. An important aspect of the application of the sol-gel method for coating metallic objects is also the deposition technique.     

基于PbI2的有机-无机杂化化合物的合成和晶体结构

合成得到了2个新的有机-无机杂化化合物{（4-CH₃-Bz-4-Ph-Py）[PbI₃]}_n（1）（其中4-CH₃-Bz-4-Ph-Py是4-甲基苄基-4-苯基吡啶阳离子）和{（4-CF₃-Bz-4-Ph-Py）[PbI₃]}_n（2）（其中4-CF₃-Bz-4-Ph-Py是4-三氟甲基苄基-4-苯基吡啶阳离子）。对化合物1和2进行了元素分析、粉末X射线衍射等表征,并利用X射线单晶衍射测定了它们的单晶结构。化合物1属于正交晶系,P2₁2₁2空间群;化合物2与1同构。结构研究表明,化合物1和2中,铅碘八面体通过共边连接方式,形成[Pb₃I₉]_n三链,有机阳离子填充在无机碘化铅链空隙中。     

基于PbI2的有机-无机杂化化合物的合成和晶体结构

合成得到了2个新的有机-无机杂化化合物{（4-CH₃-Bz-4-Ph-Py）[PbI₃]}_n（1）（其中4-CH₃-Bz-4-Ph-Py是4-甲基苄基-4-苯基吡啶阳离子）和{（4-CF₃-Bz-4-Ph-Py）[PbI₃]}_n（2）（其中4-CF₃-Bz-4-Ph-Py是4-三氟甲基苄基-4-苯基吡啶阳离子）。对化合物1和2进行了元素分析、粉末X射线衍射等表征,并利用X射线单晶衍射测定了它们的单晶结构。化合物1属于正交晶系,P2₁2₁2空间群;化合物2与1同构。结构研究表明,化合物1和2中,铅碘八面体通过共边连接方式,形成[Pb₃I₉]_n三链,有机阳离子填充在无机碘化铅链空隙中。     

基于PbBr2的有机-无机杂化化合物的合成和晶体结构

合成得到了2个新的有机-无机杂化化合物{（4-CH₃-Bz-4-Ph-Py）[PbBr₃]}_n（1）（4-CH₃-Bz-4-Ph-Py⁺=4-甲基苄基-4-苯基吡啶离子）和{（4-F-Bz-4-Ph-Py）[PbBr₃]}_n（2）（4-F-Bz-4-Ph-Py⁺=4-氟苄基-4-苯基吡啶离子）。对化合物1和2进行了元素分析、粉末X射线衍射等表征,并利用X射线单晶衍射测定了它们的单晶结构,配合物1与2同构,均属于正交晶系,P2₁2₁2空间群。结构研究表明,配合物1和2中,铅溴八面体通过共边连接方式,形成[Pb₃Br₉]_n三链,有机阳离子填充在无机溴化铅链空隙中。配合物1和2均未作手性分离。     

基于PbBr2的有机-无机杂化化合物的合成和晶体结构

合成得到了2个新的有机-无机杂化化合物{（4-CH₃-Bz-4-Ph-Py）[PbBr₃]}_n（1）（4-CH₃-Bz-4-Ph-Py⁺=4-甲基苄基-4-苯基吡啶离子）和{（4-F-Bz-4-Ph-Py）[PbBr₃]}_n（2）（4-F-Bz-4-Ph-Py⁺=4-氟苄基-4-苯基吡啶离子）。对化合物1和2进行了元素分析、粉末X射线衍射等表征,并利用X射线单晶衍射测定了它们的单晶结构,配合物1与2同构,均属于正交晶系,P2₁2₁2空间群。结构研究表明,配合物1和2中,铅溴八面体通过共边连接方式,形成[Pb₃Br₉]_n三链,有机阳离子填充在无机溴化铅链空隙中。配合物1和2均未作手性分离。     

基于有机/无机杂化钙钛矿有序结构的异质结及其光伏性能的研究

研究了一种新型的有机/无机杂化钙钛矿材料(3-BrC₃H₆NH₃)₂CuBr₄薄膜的聚集态形貌和良好的微观有序性特征, 霍尔迁移率测试结果表明该材料为p型半导体, 空穴迁移率为0.0025 cm²•V^－1•s^－1. 利用其在紫外-可见光谱范围内与C₆₀薄膜具有良好的光吸收互补性, 制备并研究了(3-BrC₃H₆NH₃)₂CuBr₄/C₆₀层状异质结结构中的暗态传输和光伏性能. 对不同退火温度下杂化钙钛矿薄膜的聚集态特性和器件性能之间的联系进行了探讨, 结果表明在低温退火条件下, 由于钙钛矿结构材料中有机组分排列更加有序, 器件显示更好的性能.     

Synthesis and Characterisation of Aluminium-Zirconium Based Organic-Inorganic Materials via Sol-Gel Route

Monolithic and transparent hybrid Al-Zr gels were obtained by the reaction of homogeneous mixtures of metal alkoxides: (Al(OBu^s)₃ + Zr(OPr)₄) with Butan-1,3-diol at room temperature, without solvent, catalyst, or water. The products have been characterized by IR spectroscopy, DTA and TGA. The results show that the diol has reacted with the mixture of alkoxides leading to the monolithic transparent gels in which both organic-inorganic (–Al–O–R–O–Zr–) and inorganic (–Al–O–Zr–O–) bridges are formed.Xerogels obtained after the drying of gels were pyrolysed at different temperatures in air. The structure and morphology of the obtained materials were studied by X-ray powder diffraction (XRD) and the Brunauer-Emmett-Teller (BET) method. At 1200°C, the materials were composed of Al₂O₃, t-ZrO₂ and m-ZrO₂.     

Optical Limiting Devices Based on C60 Derivatives in Sol-Gel Hybrid Organic-Inorganic Materials

A guest-host solid state device based on hybrid organic-inorganic materials and fullerene derivatives has been fabricated for optical limiting applications. Different 3-glycidoxypropyltrimethoxysilane derived hybrid matrices have been synthesized to increase the optical limiting performances. These matrices have shown high laser damage fluences, low light scattering, good transmittance in the visible range and allowed to deposit 10–100 m thick films per single layer. The C₆₀ derivatives have been functionalized with Si tri-alkoxide terminal groups and have reached a final concentration in the solid matrix up to 2 × 10^–2 M·l^–1. A multilayer system with a bottleneck structure has been developed to optimize a laser protection device.     

有机无机杂化太阳能电池中常见无机缓冲层材料的研究进展

有机无机杂化太阳能电池中, 电极缓冲层的选择对光电转换效率有着重要的影响. 理想的负极缓冲层兼具传输电子和阻挡空穴的作用, 而理想的正极缓冲层兼具传输空穴和阻挡电子的作用. 常见的无机电子传输材料主要有TiO₂和ZnO等, 而常见的无机空穴传输材料主要有CuI、CuSCN和NiO等. 本文就这些常见的无机缓冲层材料在有机无机杂化太阳能电池中的应用作一简要回顾, 并对其可能存在的问题进行了分析和评述.     

LC4铝合金表面电泳沉积硅锆有机-无机杂化涂层的制备及性能

采用阴极电泳沉积的方法在LC4铝合金表面制备硅锆有机-无机杂化涂层, 并探讨了电泳沉积条件对涂层形貌、结构以及耐蚀性的影响. 采用纳米粒度仪检测了不同硅锆杂化溶胶的zeta电位; 采用扫描电子显微镜(SEM)和原子力显微镜(AFM)观察了涂层的表面微观形貌和粗糙程度; 采用傅里叶红外光谱(FTIR)研究了涂层的化学结构; 采用电化学方法研究了沉积电压对涂层耐蚀性能的影响, 进而探讨了电泳沉积增强杂化涂层耐蚀性的机理. 结果显示沉积体系的pH为1.6、沉积电压为5 V时为最佳的沉积条件, 所获得的硅锆有机-无机杂化涂层表面均匀致密性最好, 粗糙程度和耐蚀性都得到了明显的改善, 在3.5% NaCl溶液中体现出较好的耐蚀作用.     

Mechanical Properties of SiO2-PMMA Based Hybrid Organic-Inorganic Thin Films

Nano-indentations using a Berkovich indenter were performed in order to analyze the mechanical properties of hybrid organic-inorganic coatings. This technique allows to measure low load deformations and therefore to estimate quantitatively mechanical properties of the coatings. The elastic modulus and the hardness were determined on the basis of the load-displacement curve. We report results obtained for class II hybrid coatings based on SiO₂-PMMA prepared by sol-gel process. The effects of coating composition were investigated.