Formation of Superhydrophobic Alumina Coating Films with High Transparency on Polymer Substrates by the Sol-Gel Method

Transparent, superhydrophobic coating films have been prepared on polymer substrates at low temperatures through the sol-gel method. Al₂O₃ gel films were prepared on poly(ethylene terephthalate) substrates from Al(O-sec-C₄H₉)₃ chemically modified with ethyl acetoacetate. A small roughness of about 20–50 nm was found to form on the surface of the Al₂O₃ gel films dried at room temperature and then immersed in hot water at 60°C. The electron diffraction measurements have shown that this roughened surface consists of pseudoboehmite nanocrystals. The coating of hydrolyzed fluoroalkyltrimethoxysilane on the Al₂O₃ gel films with the small roughness produced transparent, superhydrophobic films with contact angle for water larger than 150°.     

Study on the Superhydrophilicity of the SiO2-TiO2 Thin Films Prepared by Sol-Gel Method at Room Temperature

Nanoscale SiO₂-TiO₂ composite thin films with the thickness of about 100 nm were prepared by sol-gel method at room temperature in air. The chemical states of the elements on the surface and near the surface were measured by XPS. The results showed that the Ti on/near the surface of the thin films existed not only as TiO₂ but also as Ti₂O₃. Part of the TiO₂ was changed to Ti₂O₃ after UV irradiation. The crystalline structure of the TiO₂ in the SiO₂-TiO₂ thin films was anatase with the crystallite size of 14–20 nm. It was found that the thin film prepared at room temperature in air has good superhydrophilic property and has strong adherence to the substrate.     

超疏水表面黏附性的研究进展

结合作者课题组的相关工作,简要地论述了超疏水表面固液黏附性的主要影响因素和评价标准,介绍了天然和人工仿生具有特殊黏附性超疏水表面的研究进展,包括超疏水高黏附表面、超疏水低黏附表面、可控黏附性超疏水表面、各向异性黏滞力超疏水表面、黏滞力响应性智能超疏水表面以及超亲/超疏水图案表面制备及运用.特别介绍了作者研究小组在仿生可控黏滞力超疏表面制备以及超亲/超疏水图案表面运用的研究.最后对具有特殊黏附性超疏表面的研究进行总结和展望.     

紫外光辐照制备超亲水再生丝素蛋白膜

众多的研究已表明生物材料的表面润湿性(wettability)对于细胞的粘附有重要的影响. 在通过浇铸成膜并辅以乙醇后处理方法制备非水溶性再生丝素蛋白膜的基础上,我们采用紫外光辐照的方法以改变此类丝素蛋白膜的表面特性. 接触角测试的结果显示,随着紫外光照时间的增加,丝素蛋白膜表面与水的接触角逐渐降低,最终可以达到超亲水的状态;表面X射线光电子能谱(XPS)分析表明,这是由于丝素蛋白膜表面亲水性基团(包括羧基和羰基等)的含量随着紫外光照时间的延长而增加所致. 同时我们发现,经紫外光辐照一定时间后,再生丝素蛋白膜的力学性能并没有发生显著的降低. 显然,此类具有较高力学性能且表面亲水性能较好的再生丝素蛋白膜有可能被进一步应用于生物医学领域.     

溶胶-凝胶法制备稀土铽配合物掺杂的发光薄膜

采用溶胶－凝胶法原位制备了稀土配合物掺杂的发光薄膜，薄膜透明均一。结果表明用原位合成法，可以将难溶性稀土羧酸类配合物有效地掺杂到溶胶基质中，荧光光谱分析表明，所得到的薄膜材料在紫外激发下发射出铽离子的特征发射线。     

溶胶-凝胶法制备金属铂高分散的二氧化钛薄膜

Uniform and crack free TiO 2 thin films with highly dispersed platinum were prepared from i PrOH TTIP DEA H 2O system containing H 2PtCl 6·6H 2O as metal source by sol gel method. The microstructure and morphology of the films were characterized by TEM and XRD respectively. It was found that the Pt particles dispersed in the films and had a homogeneous distribution in the shape of sphere with an average size of about 5 nm. This study also showed that the doping with few percent of Pt resulted in the formation of pure rutile phase at a temperature as low as 550 ℃, whereas the same pure phase was formed at the temperature higher than 650 ℃ in TiO 2 or Au/TiO 2 thin films.     

石墨烯氧化物薄膜电极的光电化学特性

采用浸渍-提拉法制备了一系列石墨烯氧化物(GO)薄膜,并通过X射线衍射(XRD),扫描电镜(SEM),傅里叶变换红外光谱,紫外-可见吸收光谱和光电化学测量等技术对样品进行了表征.在GO电极上观察到阴极光电流,且光电流密度受薄膜的厚度影响.GO薄膜电极厚度为27nm时,光电流密度为0.25μA·cm-2.此外,GO电极的光电响应还受紫外光照影响,随着紫外光照时间的延长,阴极光电流逐渐减小.该工作提供了简便的通过控制薄膜厚度或紫外光照时间来控制GO薄膜半导体光电化学性能的方法.     

Selective Electroless Deposition of Cu on an Ultrathin Au Film Pattern

Summary: In this report an ultrathin Au nanoparticle (AuNP) film composed of photosensitive diazoresin (DR) and mercaptophenol (MP) capped AuNPs (MP‐AuNPs) was fabricated by self‐assembly (SA). The DR/MP‐AuNP film was then patterned through a photomask by selective exposure to UV light and instantly developed in sodium dodecyl sulfate (SDS) aqueous solution. After sintering at 550 °C to remove the organic components, the DR/MP‐AuNPs formed AuNPs. Taking advantage of the catalytic susceptibility of AuNPs toward electroless deposition of Cu, a Cu film micropattern with fine resolution (ca. 2–3 μm) and considerable thickness (ca. 130 nm) was prepared.

SEM image of the micropatterned Cu film on a silicon substrate; scale bar: 10 μm.     

Sol-Gel Formation of ITO Thin Film from a Sol Including ITO Powder

Recently, low temperature synthesis of ITO thin film of low resistivity is desired in the field of LCD (Liquid Crystalline Display) production. This paper describes the results of experiment to produce ITO thin film from a sol containing crystalline ITO particles and alkoxides of In and Sn. Crystallization temperature of ITO thin film obtained from the sol mixed with ITO powder was lower than that of ITO from the sol without ITO powder. Furthermore, the resistivity of the former ITO thin film was lower than that of the latter. It was assumed that these results were attributed to the promotion effect of ITO crystalline particles to crystalize the amorphous ITO gel at lower temperature. This low temperature crystallization effect plays an important role in enhancing the crystallinity and electric conductivity of ITO thin film from sol-gel process.     

Preparation of Alumina Supported Palladium Catalysts by Sol-Gel Method

The chemical reactivity of the aluminium-sec-butoxide (ASB) and the palladium acetylacetonate Pd(acac)₂, used as precursors for the preparation of the alumina supported palladium catalysts by sol-gel method was investigated by the spectroscopic study of the precursor mixture during ageing, using FTIR, UV-VIS and ²⁷Al NMR. The obtaind results showed that acetylacetonate ligands were linked to aluminum when the mixture was aged at 40°C. This was proved by the bands observed at 1530 and 1600 cm^–1 in the FTIR spectra, the band obtained at 289 nm in the UV-VIS spectra and the ²⁷Al NMR sharp peak at 3 ppm. Furthermore, in order to avoid the Pd(acac)₂ reduction to metallic palladium by the SB occurring when the mixture is aged for 3 h, an optimum ageing time should be selected. The precursors modification and the preservation of the palladium oxidation state during ageing could be the required conditions to create a bond between palladium and aluminium during the gelation step. This should be the reason of the thermal stability improvement of the alumina supported palladium catalyst prepared by the sol-gel method.     

光化学法合成银纳米线及其形成机理的研究

结合晶种法和光化学还原法,在聚乙烯吡咯烷酮(PVP)的诱导下成功地制备出直径为50～120nm,长度约为50μm的银纳米线以及银的树枝状纳米结构．实验表明各种反应条件如聚乙烯吡咯烷酮和硝酸银的摩尔比、晶种的加入量及反应时间等对纳米产物的形貌有影响．根据实验结果提出了一种新的银纳米线的形成机理．     

溶胶凝胶法制备超疏水二氧化硅涂膜及其表面润湿行为

采用溶胶-凝胶法以正硅酸乙酯(TEOS)和甲基三乙氧基硅烷(MTES)为前驱体制备超疏水SiO2涂层。红外光谱(FTIR)和热重分析(TGA)表征合成SiO2的化学组成,通过透射电镜(TEM)和扫描电镜(TEM)观察制备SiO2的结构形貌,扫描电镜(SEM)和原子力显微镜(AFM)观察SiO2涂膜的表面形貌,通过测试水接触角(WCA)讨论SiO2涂层的表面微观结构与其表面疏水性能的关系。结果表明以TEOS和MTES为共前驱体可以制备得到表面带-CH3基团的SiO2溶胶,SiO2溶胶在老化过程中纳米SiO2粒子由于自组装作用形成草莓状微米-纳米双微观结构,这种结构赋予SiO2涂膜表面不同等级的粗糙度,使得水滴与涂膜表面接触时能够形成高的空气捕捉率和较小的粗糙度因子,与SiO2表面疏水性的-CH3基团共同作用形成类荷叶超疏水结构。     

Synthesis of New Hybrid Organic-Inorganic Alumina Gels by the Sol-Gel Method

New hybrid organic-inorganic alumina gels have been prepared by reacting aluminum sec-butoxide and propane-1,2-diol, in CCl₄ as solvent. This reaction occurred without water addition and without the use of any catalyst, leading to the formation of transparent and monolithic gels. IR,²⁷Al and¹³CNMR show that an interchange reaction between OBu ^s alkoxide groups and diol groups occurred, leading to the hybrid gels. Samples heat treated at different temperatures under argon are weakly porous and have a small specific surface area. XRD indicates the presence of pure α-alumina at 1450°C.     

Control of Optical Properties of Thin Films Doped with Au Fine Particles by the Sol-Gel Method

We have developed tinted glasses with thin films doped with Au particles by the sol-gel method for automotive windows. Pink-colored glasses are mass-produced. The observed color is from absorption due to surface plasma resonance of Au particles. The squeeze-out of fine Au particles out of gel films was restrained by an organic additive. The index of the matrix was adjusted by the mixing ratio of TiO₂ (refractive index n = 2.20) to SiO₂ (n = 1.46). The absorption of Au particles is more intense with the higher index of the matrix, and its peak varies from 530 nm for n = 1.46 to 630 nm for n = 2.20, which yields a transmission color from pink to blue. The combination of the color of the glass substrate and the absorption by the Au particles in the thin films with various indices yields a variety of tinted glasses such as pink, orange, blue, blue-green and gray.     

Nonlinear Optical Susceptibility of Fe2O3 Thin Film Synthesized by a Modified Sol-Gel Method

The homogeneous transition metal oxide Fe₂O₃ thin films are synthesized in a modified sol-gel process by spin coating. The third order nonlinear optical susceptibility of the film is about 2 × 10^–9 esu at 488 nm wavelength by the z-scan method with a 180 femtosecond pulse laser beam. The film is expected to be useful for the application of nonlinear optical devices.     

Electrical and Optical Properties of MgO Thin Film Prepared by Sol-Gel Technique

MgO thin films with either (111) or (200) preferential orientation have been prepared on (100) Si substrates by sol-gel method after a heat-treatment at 800°C. The obtained (111) preferentially oriented MgO film has a dielectric constant of 7.0 with a loss factor of 5% and a dielectric strength higher than 8 × 10⁵ V/cm. The optical refractive index, which depends on the film thickness, is 1.71 when the film thickness is 260 nm. The surface structure of the Si substrate is believed to affect the preferential orientation of the sol-gel derived MgO film. Specifically, the microstructures at the interface indicate an interdiffusion of Mg, O, and Si between the film and the substrate.     

Photoconductive UV Detectors Based on ZnO Films Prepared by Sol-Gel Method

Highly c-axis oriented ZnO thin films were deposited on single crystal Si (111) substrates by sol-gel method. The photoconductive UV detectors based on ZnO thin films, being a metal-semiconductor-metal (MSM) structure with interdigital (IDT) configuration, were fabricated by using Au as contact metal. The characteristics of dark and photocurrent of the UV detector, the UV photoresponse of the detector were investigated. The linear current-voltage (I-V) characteristics under both forward and reverse bias exhibit ohmic metal-semiconductor contacts. Under illumination using monochromatic light with a wavelength of 365 nm, photo-generated current arrived at 44.89 μ A at a bias of 6 V. The detector exhibits an evident wide-range spectral responsivity and shows a trend similar to that in photoluminescence (PL) spectrum. PL spectrum of detector exhibits two peaks, one is the near band edge emission, and another is the deep-level emission in the visible region.     

氧化铝薄膜表面羰基钼物种的可逆再生

 通过Mo(CO)6的热分解制备了Al2O3薄膜负载的金属钼模型催化剂,并采用热脱附谱(TDS)和X射线光电子能谱(XPS)原位研究了CO在金属态Mo/Al2O3模型催化剂表面的化学吸附. 结果表明,在低温下CO可与Al2O3表面的金属钼纳米粒子发生多重配位形成类似于羰基钼的物种. CO在Mo/Al2O3模型催化剂表面的吸附导致Mo 3d XPS峰向高结合能方向位移,所生成的羰基钼物种表现为TDS谱中在240 K处有脱附峰. 负载的金属钼模型表面与体相金属钼的化学性质完全不同,表现出明显的粒子尺寸效应.     

Epitaxially Grown LaSrCoO3 Thin Films on Various Substrates by the Sol-Gel Method

LaSrCoO₃ thin films have been prepared on various substrates by the sol-gel method using inorganic salts as starting materials. The crystallinity and in-plane alignment of the films were analyzed by X-ray diffraction -2 scans and scans (pole-figure analysis), respectively. Highly (h00)/(00l)-oriented LaSrCoO₃ films with crack-free surfaces were obtained by annealing at 800°C on SrTiO₃(100), while films grown on MgO(100) and Si(100) exhibited poor crystallinity. According to the X-ray diffraction -2 scan, crystallinity of the product films was found to depend on lattice-misfit values between the films and the substrates used. On the contrary, the lattice-misfit values were less effective to the epitaxy of the LSCO film. Epitaxial film grown on SrTiO₃ annealed at 800°C was found by reciprocal-space mapping (-2 scan) analysis to consist of the pseudocubic phase.     

Characterisation and Catalytic Properties of Vanadium Oxide Supported on Alumina Prepared by Sol-Gel Method

Vanadia-alumina xerogels were prepared by sol-gel method using organic precursors of metal and acetic acid as hydrolysis source. The purpose of this work is to study the change in the structure of dispersed vanadia as a function of preparation parameters, mainly the hydrolysis ratio k = [CH₃COOH]/[Al(O-s-Bu)₃] and the vanadium content V/V + Al (%).The amount of acetic acid affects considerably the solid texture, thus the pore size increases with the k ratio. In the same time, ⁵¹V NMR spectroscopy shows a decrease in the vanadium coordination from six-fold to fourfold. The investigation by temperature programmed reduction (TPR) shows that the reducibility of catalysts is determined in the order: K = 3 > K = 2 > K = 1. Furthermore, the catalytic activity in paraxylen oxidation follows a trend similar to that observed in TPR.The increase of vanadium content from 5 to 10%, favours the association of vanadium monomeric species, resulting in a new surface species. Hence, the coordination of vanadium changes from tetrahedral to octahedral, which induces a fall in partial oxidation selectivity.