溶胶-凝胶法制备桥式聚倍半硅氧烷/SiO2光学防潮膜

采用溶胶-凝胶法, 以首次合成的具有桥式结构的间苯二亚甲基二脲基丙基三乙氧基硅烷(m-XDUPTEOS)和正硅酸乙酯(TEOS)为前驱体, 共同水解缩聚制备了不同摩尔配比的桥式聚倍半硅氧烷/SiO₂杂化溶胶, 并旋涂制膜. 通过UV-Vis, AFM和TGA对薄膜的光学性能、表面形貌和热稳定性进行了分析. 结果表明, 该薄膜平整均匀、具有良好的光学透明性、热稳定性和防潮性能.     

CuO-SiO2和Cu2O-SiO2薄膜的制备及其光学性能

以CuSO₄·5H₂O和正硅酸乙酯为前驱体,配制了稳定透明的Cu²⁺-SiO₂复合溶胶电解液。采用电化学-溶胶凝胶方法,在恒电位-0.9 V下得到Cu-SiO₂复合膜,该复合薄膜分别在250和450℃的热处理后得到Cu₂O-SiO₂和CuO-SiO₂复合薄膜。采用XRD、SEM/EDX和台阶仪表征了复合薄膜的组成、形貌和厚度;采用紫外-可见光谱和Z扫描技术研究了复合薄膜的线性和三阶非线性光学性能。结果表明Cu₂O-SiO₂和CuO-SiO₂复合薄膜中的Cu含量、Cu的形态（如Cu₂O、CuO）及Cu₂O或CuO颗粒大小影响薄膜的光学带隙和三阶非线性光学性能,2种薄膜的光学带隙分别是2.67和2.54 eV,三阶非线性极化率χ^（3）分别为2.31×10^-6和1.36×10^-6 esu。     

不同nCu2+:nCit3-的Cu(Ⅱ)-Cit3--SiO2溶胶中电沉积制备CuxO-SiO2复合薄膜

以醋酸铜(Cu(Ac)₂)和正硅酸乙酯(TEOS)为前驱体,柠檬酸钠(Na₃Cit)为配合剂,在室温下制备出物质的量之比n_Cu²⁺:n_Cit^3-为1:1和1:2的两种透明稳定的Cu(Ⅱ)-Cit^3--SiO₂复合溶胶。以此为电解液,采用恒电位方法,在ITO阴极上直接制备出了Cu_xO-SiO₂复合薄膜。CV(循环伏安)和XRD(X射线衍射)结果表明,在低过电位和高过电位分别得到Cu₂O-SiO₂和Cu/Cu₂O-SiO₂薄膜。XRD和EDX(X射线散射能谱)结果表明,相同沉积条件下,n_Cu²⁺:n_Cit^3-为1:1溶胶中得到的薄膜中Cu含量较1:2溶胶中的高。薄膜在两种溶胶中的电化学形成机理不同,其原因在于溶胶中Cu(Ⅱ)存在的形式不同。CA(计时安培)和SEM(扫描电镜)结果一致表明,Cu和Cu₂O在两种溶胶中的成核机理与电位有关,随着过电位增大,成核机理从三维连续成核逐渐转向瞬时成核。     

溶胶凝胶法制备β-环糊精聚合物/二氧化钛有机-无机杂化材料

通过烯丙基环糊精(allyl-β-CD)与丙烯酸(AA)的共聚合反应在环糊精聚合物链中引入了活性基团羧基, 运用溶胶-凝胶法制备了新型的环糊精聚合物P(CD-co-AA)/TiO₂有机-无机杂化材料. 溶剂抽提结果和FT-IR表明杂化材料中有机无机两相间存在着化学键. 通过XRD, SEM, TGA研究表明有机无机两相高度相容, 热稳定性能有大大的提高. 另外还发现, 在所制的材料中TiO₂的含量对材料的结构和性能有很大的影响, 当TiO₂的含量为60% (w)时, 材料表面均匀光滑, 有机无机两相相容性和材料的热稳定性能最好.     

FexOy/SBA-15介孔分子筛的合成以及性能研究

在酸性溶液中利用溶胶凝胶-pH值控制两步法直接合成Fe_xO_y/SBA-15介孔分子筛，同时利用场发射扫描电子显微镜(FESEM)、小角度X射线衍射(Low-angle XRD)、透射电子显微镜(TEM)以及振动样品磁强计(VSM)对制备的各种SBA-15介孔分子筛进行结构以及性能的测试、表征。结果显示Fe_xO_y均匀地分散在SBA-15的骨架中，而且会对SBA-15介孔分子筛起钉轧作用。而后着重研究了Fe_xO_y的加入对SBA-15介孔分子筛的热稳定性、催化特性以及磁学性能的影响。Fe_xO_y的引入可以增加制备的SBA-15介孔分子筛的热稳定性;Fe_xO_y的引入可以改善SBA-15介孔分子筛的催化活性，得到了开口的、石墨化程度较好的纳米碳管。Fe_xO_y的引入使SBA-15介孔分子筛具有明显的铁磁性。     

二维配位聚合物[Cd(C4O4)(C12N2H8)(H2O)]n的合成、晶体结构与性能研究

本文采用邻菲罗啉和方酸为配体，在水热条件下通过自组装合成了具有二维网状结构的配位聚合物[Cd(C₄O₄)(C₁₂N₂H₈)(H₂O)]_n，并应用X-光衍射技术测定了其单晶结构。结果表明：Cd原子与2个邻菲罗啉氮原子、3个方酸氧和1个水分子配位，生成了六配位扭曲八面体。方酸以少见的μ-1，2，3配位模式桥联3个中心金属离子，并进一步组装成二维网状配位聚合物。对配位聚合物的光学性能及热稳定性做了进一步的研究，实验结果表明：配位聚合物是具有良好热稳定性的强荧光材料，具有潜在的应用前景。     

Mn2+掺杂准二维钙钛矿(PEA)2PbyMn1-yBr4的制备及其电致发光性能

制备了具有高荧光量子产率(photoluminescence quantum yield, PLQY)的 Mn²⁺掺杂准二维钙钛矿(PEA)₂Pb_yMn_1-yBr₄(PEA为苯乙胺, y 为 Pb²⁺占 Mn²⁺和 Pb²⁺总含量的物质的量分数)薄膜。宽带隙的(PEA)₂PbBr₄作为给体, 掺杂杂质 Mn²⁺作为受体, 构筑了双发射的激发态传递系统。通过调控 Mn²⁺掺杂的不同比例对(PEA)₂Pb_yMn_1-yBr₄的发光性能和薄膜形貌的影响, 发现当前驱体溶液中 Mn²⁺与 Pb²⁺的物质的量之比为 1:4 时, 薄膜有着最高的 PLQY 和最低的表面粗糙度。利用飞秒瞬态吸收(transientabsorption, TA)光谱, 追踪其动力学过程, 发现主客体之间的激发态传递是通过电荷转移来实现的。为了研究材料的电致发光特性, 我们将(PEA)₂Pb_yMn_1-yBr₄作为活性层, 加工得到了发光二极管(light emitting diodes, LEDs)。在室温下, 器件发出明亮的橙色, 其最高的发光强度为 0.21 cd·m^-2, 外量子效率(external quantum efficiency, EQE)为 0.002 5 %。     

具有稳定可见光催化活性TiO2薄膜的常温制备

采用溶胶-凝胶法，通过钛酸丁酯水解制备了具有锐钛矿-金红石-板钛矿混晶晶粒的TiO₂溶胶。以四磺酸酞菁铜(CuTsPc)为敏化剂，经水浴加热后获得具有可见光响应活性的TiO₂溶胶。使用该溶胶浸渍-提拉涂膜，在室温下晾干即可得到酞菁敏化的TiO₂薄膜(CuTsPc-TiO₂)。对敏化溶胶的制备条件及薄膜的性能进行了考察，并探讨了CuTsPc的负载机理。结果表明:延长水浴时间或提高TiO₂溶胶中的CuTsPc浓度有利于增大薄膜中CuTsPc的负载量。随着薄膜中CuTsPc量的增加，薄膜的可见光催化活性增强，但CuTsPc负载过多又会导致薄膜光催化活性降低。CuTsPc通过静电作用在TiO₂胶粒表面发生吸附，从而实现在薄膜中均匀、牢固的负载，保证了CuTsPc-TiO₂薄膜在循环使用过程中的稳定性。     

室温下制备以{211}晶面为主的Ti1-xVxO2薄膜及其可见光催化性能

以金属Ti和V作为靶材,采用直流反应共溅射技术在室温下制备了以{211}晶面为主的锐钛矿相Ti_1-xV_xO₂薄膜,研究了不同V靶功率对Ti_1-xV_xO₂薄膜的薄膜成分、晶相结构和可见光催化性能的影响。研究表明,Ti_1-xV_xO₂薄膜的晶相结构为锐钛矿相,择优取向为(211),而结晶度受V靶功率的影响。随着V靶功率的增加,薄膜中V元素含量逐渐增加,同时,晶粒和沉积速率也逐渐增加。另外,当V靶功率为150W时,薄膜的表面粗糙度值有一个最大值。V的掺杂导致薄膜的能带间隙变窄,对光的吸收向可见光区偏移,从而有效地改善了薄膜的可见光催化能力。当V靶功率为150W时,Ti_1-xV_xO₂薄膜的能带间隙值为2.82eV,其在2h的可见光照射下分解了80%的RhB染料。这被归结于能带间隙窄,高能晶面{211}和结晶度高的共同作用。     

高折射率有机/无机纳米杂化透明膜层材料的制备与性质研究

采用溶胶-凝胶法,将钛酸酯和硅烷偶联剂(KH-560)进行共水解,经涂膜、固化,制备了一系列含有无机二氧化钛纳米相的无机/有机杂化膜层材料,通过不同方法对杂化膜层的微结构、光学、机械和热性质进行了表征.结果表明,所得到的有机/无机纳米复合膜层,在可见光范围内的透过率均在90%以上,同时具有较好的耐热性和较高的折射率(nd=1.47~1.73),并且膜层与基材的附着性好,铅笔硬度达到4~5H.     

The synthesis and characteristic study of 6FDA-6FHP-NLO polyimide/SiO2 nanohybrid materials

Hybrid nanocomposite films of silica (SiO₂) in polyimide (PI) from 4,4^′-(hexafluoroisopropylidene) diphthalic arhydride (6FDA), 2,2-Bis (3-amino-4-hydroxyphenyl) hexafluoropropane (6FHP) and nonlinear optical (NLO) molecule have been successfully fabricated by an in situ sol-gel process. The silica content in the hybrid films was varied from 0 to 22.5 wt%. These nanocomposite films exhibit fair good optical transparency. Fourier transform infrared (FTIR) spectroscopy results confirm the formation of SiO₂ particles in PI matrix. Scanning electron microscope (SEM) images show that the SiO₂ phase is well dispersed in the polymer matrix. Their glass transition behavior and thermal stability were investigated by differential scanning calorimeter (DSC) and thermal gravimetric analysis (TG).     

A Study on Liquid Hybrid Material for Waveguides—Synthesis and Property of PSQ‐Ls for Waveguides

Silicate‐based inorganic‐organic hybrid polymer systems have many unique properties including thermal stability and photo‐stability, chemical resistance with the combination of tunable optical properties. Two kinds of new UV‐patternable hybrid materials PSQ‐Ls were synthesized by a sol‐gel process at room temperature, which can be used for low cost fabrication of optical waveguides. Thick films (up to 8.31 µm) can be coated by a single spin‐coating process without any cracking and the average surface roughness (Ra), detected by atomic force microscopy (AFM), is below 0.5 nm. The optical properties (refractive index, birefringence, and optical loss at 1310 nm and 1550 nm, respectively) of the PSQ‐Ls films are investigated by a prism coupler. The refractive index of PSQ‐Ls can be exactly tuned from 1.4483 to 1.5212 by blending PSQ‐LH (n_TE=1.5212 @ 1310 nm) and PSQ‐LL (n_TE=1.4483 @ 1310 nm). The maximum refractive index contrast is about 4.8%. After post‐baking, birefringences of the films are below 0.0005 and optical losses are about 0.2 dB · cm^?1 at 1310 nm, 0.7 dB · cm^?1 at 1550 nm, respectively. Furthermore, the PSQ‐Ls films also show outstanding thermal stability in air atmospheres.     

Flexible nanocrystalline‐titania/polyimide hybrids with high refractive index and excellent thermal dimensional stability

In this study, a novel synthetic route was developed to prepare polyimide–nanocrystalline–titania hybrid optical films with a relatively high titania content (up to 50 wt %) and thickness (20–30 μm) from soluble polyimides containing hydroxyl groups. Two series of newly soluble polyimides were synthesized from the hydroxy‐substituted diamines with various commercial tetracarboxylic dianhydrides. The hydroxyl groups on the backbone of the polyimides could provide the organic–inorganic bonding and resulted in homogeneous hybrid solutions by controlling the mole ratio of titanium butoxide/hydroxyl group. AFM, SEM, TEM, and XRD results indicated the formation of well‐dispersed nanocrystalline‐titania. The flexible hybrid films could be successfully obtained and revealed relatively good surface planarity, thermal dimensional stability, tunable refractive index, and high optical transparency. A three‐layer antireflection coating based on the hybrid films was prepared and showed a reflectance of less than 0.5% in the visible range indicated its potential optical applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1433–1440, 2010     

The role of thermal analysis in optimization of the electrochromic effect of nickel oxide thin films, prepared by the sol–gel method: Part II

Thin films and the corresponding xerogels were prepared from nickel acetate precursor using the sol–gel dip-coating technique. The differences in thermal stability of the two forms of samples were studied by dynamic and isothermal thermogravimetry. For thin films, the onset decomposition temperature of acetate groups was 230 °C and for the xerogel 250 °C. During thermal decomposition, the formation of nanosized nickel oxide took place. Carbonate ions, which were formed during thermal decompostion of acetate groups, remained either free or bidentately coordinated to nickel. In situ monochromatic optical transmittance changes showed that an optical stability up to the 100th cycle was already achieved for films heated for 15 min at the isothermal temperature (thermal decompositon 25%). Comparison of the results obtained for nickel sulfate (Part I) and nickel acetate precursors shows that at least two parameters, the precursor used and the degree of thermal treatment, have considerable influence on the thermal stability of the thin film and also on its electrochromic response during the cycling process.     

Synthesis and characterization of functionalized carbon black/poly(vinyl alcohol) high refractive index nanocomposites

Carbon black(CB)/polymer composites with high refractive index(RI) were fabricated from poly(vinyl alcohol) (PVA) and covalently functionalized nano-CB(PVA-es-CB) by simple esterification reaction.Transmission electron microscopy showed that uniform aggregates of PVA-es-CB nanoparticles with a size smaller than 100 nm formed in the nanocomposite films.EUipsometric measurements indicated that the PVA-es-CB/PVA composite films had a RI in the range 1.520-1.598 linearly increased with the PVA-es-CB volume content.Theoretical equation based on Lorentz-Lorenz theory provided reasonably close estimation of the refractive indices to the experimentally observed values.The hybrid films also revealed relatively good surface planarity,thermal stability and optical transparency.     

Preparation and Z-Scan nonlinear optical characterization of Au/SiO2- and Ag/SiO2-supported nanoparticles dispersed in silica sonogel films

Au/SiO₂ and Ag/SiO₂ supported metal-nanoparticles (MNPs) were implemented to fabricate SiO₂-based inorganic?Cinorganic hybrid sonogel films. Prepared Au/SiO₂- and Ag/SiO₂-MNPs exhibited low 2D-HCP crystallinity with particle diameters below 10?nm and homogeneous size distribution. The catalyst-free (CF) sonogel route was successfully implemented to produce these optically active nanocomposite films by doping the liquid sol-phase with these MNP systems and its subsequent deposition onto glass substrates via standard spin-coating procedures. The easy MNP-loading within the mesoporous dielectric sonogel network evidenced a huge chemical affinity between the silica sonogel hosting system and the guest SiO₂-supported MNPs. This fact allowed us to fabricate high quality hybrid films suitable for cubic nonlinear optical (NLO) characterizations via the Z-Scan technique. Indeed, the hosting sonogel network provided adequate thermal and mechanical stability protecting the active MNPs from environment conditions and diminished their tendency to aggregate; thus, preserving their pristine optical properties and morphology, giving rise to stable sol?Cgel hybrid films appropriate for photonic applications. Comprehensive morphological, structural, spectroscopic and nonlinear photophysical characterizations were optimally performed to the developed hybrid films. Our results have shown that the crystalline nature of the implemented MNPs, their small sizes and appropriate guest?Chost stabilizing interactions play a crucial role in the observation of improved cubic NLO-properties of these MNP structures embedded within the highly pure CF-sonogel confinement.     

SYNTHESIS AND ELECTRICAL PROPERTIES OF POLYIMIDE-Al2O3 COMPOSITES

Polyimide-alumina hybrid films were synthesized via in situ polymerization and thermal imidation process from a solution of polyimide precursor and nanosized alumina in N,N-dimethylacetamide, and the microstructure of the hybrid films was characterized by transmission electron microscope （TEM） and infra-red （IR） spectrometry. The dependence of thermal stability, tensile properties, dielectric properties and degradation endurance under corona on the nano-Al2O3 content of polyimide-alumina hybrid films was studied. The results show that with the increase of Al2O3 content, the thermal stability and the dielectric properties of the hybrids increase, while the tensile properties decrease. Better corona resistance can be achieved if the PI film is filled with α-Al2O3 nanometric particle.     

Enhanced thermal stability of dipole alignment in inorganic-organic hybrid films containing benzothiazole chromophore

A new thermally stable second-order nonlinear optical (NLO) inorganic-organic hybrid film was successfully prepared by using a sol-gel process of alkoxysilane dye containing a benzothiazole unit. The dye-bonded precursor was synthesized from 3-isocyanatopropyltriethoxysilane and the heterocycle azo dye 2-[4'-(N-ethyl-N-2-hydroxyethyl)-amino-phenylazo]-6-nitrobenzothiazole (EHNBT) via a urethane reaction. Molecular structural characterization for the resultant was achieved by elemental analysis, FTIR, UV-visible spectra, and 1H NMR. The second harmonic coefficients (d33) of poled hybrid films measured by a Maker fringe technique were in the range 15.9-72.1 pm/V at a wavelength of 1064 nm, depending on the concentration of alkoxysilane dye. The hybrid films containing the benzothiazole moiety exhibited higher thermal stability of dipole alignment at elevated temperatures than their analogues with a benzene ring. The d33 value of the poled film remained at 94% of its initial value after heating at 120 degrees C for 6 h, and only 18% decayed in 15 min at 180 degrees C. The result indicates that the hybrid film is suitable for the fabrication of an electro-optic device.     

Radiation-induced polymerization and grafting of β(−)pinene on silica surface

Poly-β-pinene (pBp) was obtained on silica surface by γ radiation-induced polymerization of β(−)pinene in presence of silica gel with a specific surface area of 300 m²/g. Different radiation doses were employed in the range 50–332 kGy. The pBp–silica hybrid samples obtained have been characterized by FT-IR spectroscopy and the amount of pBp on silica surface has been determined both by gravimetric and TGA measurements. The fraction of pBp chemically grafted on silica surface has been determined by the extraction of the pBp–silica hybrid with boiling toluene and was found to be 10–20% of the total pBp formed on silica surface. The optical activity of pBp extracted from the hybrid was studied by polarimetric measurements and found slightly lower than the typical specific optical rotation of pBp polymerized in bulk with radiation. The thermal stability of the pBp–silica hybrid materials was studied by thermogravimetric and differential thermal analysis. The results show lower thermal stability for the pBp–silica hybrid in comparison to pure pBp. Evidently, silica catalyzes the thermal decomposition of pBp at lower temperatures. Use of the pBp–silica hybrid as stationary phase for liquid chromatography for chiral separations has been proposed.