Eu(TTFA)3掺杂SiO2杂化胶体球的合成及特性

采用改进的碱催化法和种子法分别制得了稀土配合物Eu(TTFA)₃掺杂的SiO₂杂化胶体球,并用透射电子显微镜和荧光分光光度计对其显微形貌和荧光光谱特性进行了详细地研究.结果表明,两种方法都可以获得单分散性的、稀土配合物掺杂SiO₂杂化胶体球,且都具有Eu³⁺离子典型的荧光光谱特性.Eu(TTFA)₃掺杂入SiO₂胶体球中后,有机配体TTFA在短波长处的吸收明显增强了,最大的吸收峰位也向短波长方向移动大约20～30 nm,Eu³⁺离子5D0→7F2发射跃迁仍然具有良好的窄线发光特征,同时荧光峰值的形态和位置受SiO₂基体的影响发生轻微的变化.     

超低密度SiO2气凝胶的制备及成型研究

 以正硅酸乙酯(TEOS)为硅源，采用酸碱二步催化溶胶-凝胶法，结合超临界干燥技术制备了超低密度SiO₂气凝胶,最低密度为3.4 mg/cm³；进一步结合成型工艺，在解决了模具设计和脱模技术后制备了具有不同密度的柱状和微型套筒样品，密度10～50 mg/cm³。研究了水、催化剂、稀释剂对二步溶胶-凝胶过程的影响，获得了制备低密度SiO₂气凝胶的最佳条件。利用扫描电镜、孔径分布及比表面积测试仪等对SiO₂气凝胶微结构进行了研究。结果表明，获得的超低密度SiO₂气凝胶具有较好的纳米网络，平均孔径18.9 nm，还具有高比表面积898 9 m²/g。     

多孔TiO2/Al/SiO2纳米复合结构的紫外光吸收特性研究

在SiO₂玻璃衬底上用脉冲激光沉积(PLD)技术，分别沉积Ti和Ti/Al膜，经电化学阳极氧化成功制备了多孔TiO₂/SiO₂和TiO₂/Al/SiO₂纳米复合结构. 其中TiO₂薄膜上的微孔阵列高度有序，分布均匀. 实验研究了Al过渡层对多孔TiO₂薄膜光吸收特性的影响. 结果表明：无Al过渡层的多孔TiO₂薄膜其紫外吸收峰在27     

ZrO2/SiO2溶胶-凝胶薄膜膜层间的渗透行为

 分别以丙醇锆和正硅酸乙酯为原料，采用溶胶-凝胶工艺制备了性能稳定的ZrO₂和SiO₂溶胶。用旋转镀膜法在K9玻璃上分别制备了单层SiO₂薄膜、单层ZrO₂薄膜、ZrO₂/ SiO₂双层膜和SiO₂/ZrO₂双层膜。采用原子力显微镜观察了薄膜的表面形貌，用椭偏仪测量薄膜的厚度与折射率，用紫外-可见光分光光度计测量了薄膜的透射率。对薄膜的透射光谱和椭偏仪模拟的数据进行分析，发现SiO₂/ZrO₂双层膜之间的渗透十分明显，而ZrO₂/SiO₂双层膜之间几乎不发生渗透。利用TFCalc模系设计软件,采用三层膜模型对薄膜的透射率进行模拟，得出的透射曲线与用紫外-可见光分光光度计测量的透射曲线十分符合。     

改性SiO2气凝胶制备及其在ICF实验中的应用

 以正硅酸乙酯（TEOS）为前驱体，采用酸碱两步催化法制备了SiO₂醇凝胶。醇凝胶分别经过TEOS母液、甲基三乙氧基硅烷（MTEOS）处理后，以六甲基二硅胺烷（HMDSA）为疏水改性试剂，制备了改性SiO₂醇凝胶，醇凝胶经溶剂交换后以CO₂作为干燥介质，采用超临界干燥法制备了密度在30～100 mg/cm³的SiO₂气凝胶。用傅里叶变换红外光谱仪（FTIR）对疏水性SiO₂气凝胶进行了研究。研究结果表明,经过改性的气凝胶在潮湿环境中具有极好的尺寸稳定性和疏水性。采用精密车床加工得到了满足惯性约束聚变（ICF）物理试验要求的微柱。     

波长1064nm脉冲激光高阈值反射膜的研制

 研究HfO₂/SiO₂高反射膜的制备工艺及其激光诱导损伤阈值的比较测试,分别采用了反应蒸镀HfO₂、反应离子辅助蒸镀HfO₂、反应离子辅助蒸镀金属Hf的源材料形成HfO₂薄膜。采用这三种工艺制备了HfO₂/SiO₂高反射膜,在中心波长1064nm处,反射率 R≥99.5%,其中反应蒸镀HfO₂/SiO₂高反射膜损伤阈值最高,可达60J/cm²(1064nm,5ns)。     

层间热处理对SiO2/ZrO2双层膜的影响

 以正硅酸乙酯和丙醇锆为前驱体,用溶胶-凝胶法在K9基片上提拉镀制SiO₂/ZrO₂双层膜。采用不同实验步骤制备了2个样品,样品1镀完SiO₂后直接镀ZrO₂ ,样品2镀完SiO₂经热处理后再镀ZrO₂。采用原子力显微镜、椭偏仪、紫外-可见分光光度计对薄膜进行表征。针对SiO₂/ZrO₂双层膜,考虑到膜间渗透的影响,采用３层Cauchy模型进行椭偏模拟,椭偏参数的模拟值曲线与椭偏仪的测量值曲线十分吻合,进而发现热处理可以使SiO₂/ZrO₂双层膜之间的渗透减少近23 nm,从而提高其峰值透射率。利用输出波长1.064 mm,脉宽8.1 ns的激光束对样品进行了损伤阈值的测试,用光学显微镜观察损伤形貌,结果发现两者损伤阈值分别为13.6 J/c2和14.18 J/cm²,均为膜的本征损伤。     

低成本溶胶-凝胶法制备SiO2/TiO2双层膜的减反射与自清洁性能

将玻璃基底依次在低成本的SiO₂溶胶和TiO₂溶胶中浸渍后,在500 oC下煅烧制备了同时具备减反射与自清洁性能的SiO₂/TiO₂双层膜．该膜的光学性能与结构特征分别通过紫外-可见分光光度计和场发射扫描电镜进行了表征．同时,源于超亲水性和光催化作用的自清洁性能也凸显出来．实验结果表明制备SiO₂/TiO₂双层膜对光的透射率最高可达到95%,同时具备自清洁性能．     

一维Ni0.5Zn0.5Fe2O4/SiO2复合纳米结构的制备及其磁性能

采用溶胶-凝胶法结合静电纺丝技术制备了Ni_0.5Zn_0.5Fe₂O₄/SiO₂复合纳米纤维.利用热重-差热分析、X射线衍射、场发射扫描电镜、高分辨透射电镜和振动样品磁强计研究了前驱体纤维的热分解及相转化过程以及焙烧温度和SiO₂含量对目标纳米纤维的相组成、微观结构、形貌及磁性能的影响.结果表明,在450 ℃焙烧时,立方尖晶石结构已基本形成.随着焙烧温度由450 ℃升高到100     

硅基二氧化硅厚膜材料的快速生长

采用火焰水解法在Si片上快速淀积SiO₂厚膜材料,材料膜厚达到40μm以上,生长速率达8μm/min.然后将该材料分别在真空中/空气气氛中高温致密化处理,获得了各种形态的二氧化硅厚膜材料,包括平整度好、光滑透明的玻璃态SiO₂厚膜材料.并利用XRD、电子显微镜等仪器对SiO₂膜的表面和膜厚进行了测试分析.     

Optical nonlinearity and structural phase-transition observation of organic dye-doped polymer silica hybrid material

The optical nonlinearity of organic dye-doped poly(methyl methacrylate) (PMMA)-silica-gel hybrid material was investigated by second-harmonic-generation measurement. We found that incorporation of in situ polymerized solgel precursors into the organic dye-doped PMMA significantly improved the nonlinear optical stability of the system. However, improvement of thermal stability occurred only when a sufficient amount of silica gel was incorporated. A structural phase transition from pure polymer to a hybrid system was found near a 10-mol.% silica-gel concentration. The optimum polymer/tetraethoxysilane molar ratio is 2:1 to 1:1.     

Preparation of Poly(vinylidene fluoride)/Poly(methyl methacrylate) Blend Microporous Membranes via the Thermally Induced Phase Separation Process

The thermally induced phase separation (TIPS) process was employed to prepare poly(vinylidene fluoride)/poly(methyl methacrylate) (PVDF/PMMA) blend microporous membranes. The effect of PMMA content on the dynamic crystallization temperature of the PVDF/PMMA/sulfolane system was analyzed. The effects of PMMA weight fraction and cooling rate on the cross-sectional morphology, crystallinity, crystal structure, thermal stability, and porous structure of the resulting membranes were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and a mercury porosimeter, respectively. The mechanical properties of the membranes were evaluated by tensile tests. It was found that solid–liquid phase separation occurred in the PVDF/PMMA/sulfolane system. Scanning electron microscopy revealed that either increasing PMMA weight fraction or decreasing cooling rate will lead to a macroscopical phase separation between PVDF and PMMA. PMMA weight fraction and cooling rate had some influence on the crystallinity, porous structure, and mechanical properties, but no influence on the polymer crystal structure of the membranes. PMMA weight fraction influenced thermal stability of the final membranes but cooling rate did not.     

Effect of PMMA on crystallization behavior and hydrophilicity of poly(vinylidene fluoride)/poly(methyl methacrylate) blend prepared in semi-dilute solutions

Films of poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blend were derived from a special procedure of casting semi-dilute solutions. Hydrophilic character and crystallization of PVDF were optimized by variation of PMMA concentration in PVDF/PMMA blends. It was found that a PVDF/PMMA blend containing 70 wt% PMMA has a good performance for the potential application of hydrophilic membranes via thermally induced phase separation. The films presented β crystalline phase regardless of PMMA content existed in the blends. Thermal analysis of the blends showed a promotion of crystallization of PVDF with small addition of PMMA which induced larger lamellar thickness of PVDF, leading to the largest spherulitic crystal of PVDF (10 wt% PMMA) is about 8 μm. SEM micrographs illustrated no phase separation occurred in blends, due to the high compatibility between PVDF and PMMA.     

Novel hybrid materials with covalent bonding and rare earth ions-induced enhancing luminescence of bridged 9-amino acridine

Covalently bonded silicate/modified acridine luminescent composites have been prepared from 3-(triethoxysilyl)-propyl isocyanate (TEPIC) grafted 9-amino acridine and central metal ions. The existence of covalent linkages between TEPIC and silica matrices was introduced after hydrolysis and polycondensation processes of ethoxysilyl groups. Luminescence spectra were utilized to characterize the photophysical properties of the obtained hybrid material and the above spectroscopic data reveal that the lanthanide ions and such covalent bonds trigger the increasing blue emission intensities (4-10 times) of modified acridine. Scanning electron micrographs inferred that the hybrids were quite homogeneous and free from phase separation.     

Microstructure and interfacial interaction of polyimide/silica hybrid nanocomposites prepared with 3-aminopropyltriethoxysilane

A series of polyimide (PI)-silica hybrid nanocomposites are prepared from 3,3′,4,4′biphenyltetracarboxylic dianhydride (BPDA)-4,4′-oxydianiline (ODA) polyamic acid (PAA) and tetraethoxysilane (TEOS) or tetramethoxysilane (TMOS) by the sol-gel process. 3-Aminopropyltriethoxysilane (3-APS) is used to enhance the interfacial interaction between polyimide and silica. The morphology, interfacial interaction, and properties of the hybrids are investigated using scanning electron microscope (SEM), UV-vis spectroscopy, atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). SEM and AFM images indicate that silica particles of ca. 45-55 nm size are uniformly distributed in polyimide matrices and that the interfacial interaction between PI and TEOS is better than that between PI and TMOS. The optical transparencies of the PI/TEOS hybrids are better than that of the PI/TMOS hybrids. FTIR spectra confirm the Si O Si bond as well as the conversion of PAA to polyimide and PI/silica hybrid films. The thermal stability is increased after incorporation of the silicas in the polyimide matrix.     

Epoxy-silica hybrid materials synthesized via sol-gel process

We have successfully utilized the sol-gel method to synthesize epoxy-silica hybrid material at nanoscale. Using the sol-gel process we could overcome many disadvantages of conventional composite materials. In this research, two different methods are recommended — a one-step process and a two-step process — to synthesize epoxy-silica hybrid materials. The coupling agent, γ-glycidoxypropyl-methyldiethoxysilane (KBE-402), was utilized to modify the surface properties of the silica via the sol-gel process. The role of the coupling agent is to provide covalent bonding between the epoxy resin and silica. This method could reinforce the interfacial force of the hybrid material and promote the thermal properties of the materials. The thermal properties of the epoxy-silica materials were characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). From these results, we noted that the best reaction time in the one-step process is 2 days and the addition of the inorganic component enhanced the thermal stability of the hybrid materials. On the other hand, the two-step process led to a phase separation phenomenon after mixing epoxy resin and precursor without coupling agent. The coupling agent could avoid the phase separation problem of hybrid materials and enhance the thermal stability of the materials through this process. At the same time, the T _g of the materials increased proportionally to the content of silica from 80°C to 113°C.     

Synthesis and Characterization of Hybrid Silica/Polyimides Obtained by Sol-Gel Processing

This work reports the synthesis and characterization of some hybrid silica/polyimides obtained by the sol-gel process. These hybrids present good thermostability with the degradation process starting above 470°C. The glass transition temperatures of the hybrids are slightly higher than that of the pure polyimide film, while dynamic contact angles are lower than that of the pure polyimide. The experiments show that increasing the silica content improves the thermal stability and decreases the dielectric constant of the hybrid polyimide films. Moreover, increasing the silica content leads to a higher rigidity of the hybrid polyimide films, as was proved by dynamic mechanical analysis, and to a slight decrease of the dynamic contact angles.     

PMMA/凝胶玻璃复合材料作为非线性有机分子掺杂基质的研究

对分散红1（DR1）掺杂聚甲基丙烯酸甲酯（PMMA）／凝胶玻璃复合材料的光学二阶非线笥及其热稳定性进行了研究。结果表明,PMMA／凝胶玻璃作为一种有机／无机复合材料,是介于胶玻璃和PMMA之间的一种非线性有机分子掺杂基质。随复合材料中凝胶玻璃含量增多,所制备的非线性材料的热稳定性能变好。对非线性和热稳定性的折衷考虑,获得了制备光学二阶非线笥基质材料先体PMMA和正硅酸乙酯（TEOS）的最佳混合比例。     

聚酯/无机杂化分子间键合作用及微结构相关性的光谱研究

采用FTIR,UV-Vis,WAXD和DSC手段,研究了分子间为非共价键化学结合的PCL／SiO2高分子-无机杂化透明材料组分间的键合型式;分子间特殊氢键相互作用行为与结晶性聚合物在杂化材料中的微结构相关性。结果表明,杂化体系中PCL高分子与SiO2无机组分间的键合,主要是依赖于杂化体系中较强的分子间氢键相互作用,其作用强度随无机相TEOS含量而变化。体系中氢键相互作用增加使PCL结晶高分子的相对结晶度下降,杂化材料的光学透明性提高。同时对体系中高分子-无机组分的微相分离尺度产生影响。     

Seed cryopreservation and longevity of two Salix hybrids

The effects of desiccation and storage temperature on the viability and longevity of willow seeds was investigated using two hybrids, Salix rehderiana x (Salix x capreola) [cross 458] and Salix x sericans x Salix viminalis [cross 512]. Freshly harvested seed of both crosses survived silica gel drying down to c. 3 to 5% moisture content. Hybrid 458 seed stored in liquid nitrogen (-196C) for 3 d retained viability when equilibrated to < or = 45% RH (pre-storage), showed slightly reduced survival at 65% RH and exhibited no survival at > or =82% RH. The level of survival after 68 d for seeds pre-equilibrated to either c. 10 or 65% (5 or 10% moisture) and stored at four temperatures was -196C > -20C > 2C > 16C. At all temperatures, drier seed stored better than wetter seed. For hybrid 512, seed longevity at 20C > 40C > 60C, and a 10% fall in pre-storage seed RH resulted in a c. 2-fold increase in longevity at each storage temperature. The response of hybrid willow seeds to desiccation and cooling raises possibilities for the long-term seed conservation of Salix species by cryopreservation.