CePO4纳米微粒的帛备及表征

在醇－水溶剂中用共沉淀表面修饰法制备了烷基磷酸酯修饰的ＣｅＰＯ４纳米微粒,初步探讨了表面纳米微粒的制备条件,采用多种分析手段表征了表面修饰ＣｅＰＯ４纳米微粒的结构和润滑性能。结果表明,形成了以ＣｅＰＯ４为纳米核,有机磷化合物为表面修饰层的ＣｅＰＯ４纳米微粒,在有机溶剂中具有良好的分散性,显示出良好的减摩、抗磨和承载性能。     

表面修饰磷钼酸铵纳米微粒的合成及摩擦学行为研究

在醇 -水体系中采用同阴离子共沉淀法合成了季铵盐修饰的 (NH4 ) 3 PMo12 O4 0 纳米微粒 ,以TEM、XRD、FTIR、TGA、DSC等多种分析手段表征了这种纳米微粒的形貌和结构 ,在四球试验机上考察了它们的摩擦学性能 .结果表明所合成的杂多化合物具有Keggin骨架结构 ,微粒粒径约 2 0nm ,在有机溶剂中可良好分散 ,作为一类新型润滑油添加剂 ,具有良好的抗磨性能     

DDP表面修饰PbS纳米微粒的合成及结构表征

采用表面修饰法合成了二烷基二硫代磷酸修饰的ＰｂＳ纳米微粒,并用红外光谱,（ＩＲ）,Ｘ射线衍射（ＸＲＤ）,透射电子显微镜（ＴＥＭ）,Ｘ射线光电子能谱（ＸＰＳ）等仪器表征了其结构。结果表明,所合成的ＰｂＳ纳米微粒是ＤＤＰ表面修饰层和ＰｂＳ纳米核所构成的,且由于表面修饰层的存在,有效地阻止了纳米微粒在空气中的团聚及氧化,其平均粒径为７ｎｍ。     

铅纳米微粒用作油性润滑的摩擦学性能研究

在石蜡油 聚乙二醇的混合溶剂中 ,通过液相分散法成功地制备出了铅纳米微粒 .其中 ,石蜡油是反应介质 ,聚乙二醇是抗氧化剂 .同时 ,对铅纳米微粒的形貌和结构进行了透射电镜 (TEM)和X光衍射 (XRD)表征 .结果表明 ,铅纳米微粒呈球形 ,平均粒径为 70nm ,具有与本体铅相同的晶体结构 .另外 ,在四球试验机上表征了铅纳米微粒作为润滑油添加剂的摩擦学性能 .摩擦试验表明 ,铅纳米微粒具有良好的减摩抗磨性能 ,并能够显著改善基础油的承载能力 .磨斑表面分析表明 ,铅纳米微粒的抗磨减摩机制不是形成金属沉积膜 ,可能是在摩擦接触面形成滑动 轴承系     

BSA-SDS-Ag聚合物纳米微粒的制备及水凝胶性质的研究(Ⅱ)

本文报道用X－射线衍射（XRD），TEM和FTIR光谱考察了在不同的制备条件下BSA－SDS－Ag的SDS－Ag聚合物纳米微粒的结构，形貌以及表面性质，随制备条件的不同，微粒的表面形貌有很大的差异。体系在微也液状态下，用甲醛作还原剂，可把银离子还原为单质，进而聚集成包裹型的团状微粒，微粒粒径32－60nm；微粒表面结构复杂，表明Ag^＋先后与蛋白质中的某些氨基酸残基产生化学键合，再还原为Ag粒，进而聚合成网状结构的聚合物。     

单晶硅表面有机硅烷/Ag2O纳米微粒复合自组装膜的制备和表征

利用分子自组装成膜技术 ,在单晶硅表面制备了有机硅烷 /Ag2 O纳米微粒复合膜 .应用接触角测定仪、原子力显微镜和X射线光电子能谱仪分析表征了薄膜的组成和结构 .结果表明 ,通过硅烷偶联剂 3 氨丙基 三乙氧基硅烷在单晶硅基底表面的成功组装 ,获得了较为均匀的硅烷化表面 ,而Ag2 O纳米微粒可在硅烷化表面成功地进行组装 ,并呈亚单层排布     

长方体形CdS微粒的合成及光谱性质

采用溶胶法,以硫脲为表面修饰剂,合成了长方体形CdS微粒,并用X射线粉末衍射、透射电子显微镜、红外光谱以及荧光光谱等手段进行了表征。实验结果表明,硫脲分子中的硫原子与CdS纳米晶表面的Cd2 离子存在配位作用;硫脲分子表面修饰的CdS纳米晶为立方闪锌矿结构,具有较好的荧光性质;长方体形CdS微粒可能是由硫脲分子表面修饰的CdS初级纳米晶粒自组装组成。该研究结果为硫脲分子表面修饰的CdS初级纳米晶粒在分子组装及作为新型发光材料方面的进一步研究奠定了基础。     

Ag-Au二元纳米微粒吸收谱的计算

纳米微粒的光学性能与其表面等离子体共振关系密切.本文利用推广的Mie理论计算研究了Au-Ag体系单质、合金以及核壳结构纳米颗粒的消光、吸收和散射的性能(包括壳核结构Ag-Au微粒在紫外-可见光的吸收性能),计算结果与实验值相符合得很好.研究表明,随着粒径的增加,微粒表面等离子体共振偶极吸收峰出现红移,波峰位置与纳米微粒的尺寸具有线性关系.壳核结构中,粒径与核壳比决定了整个微粒的吸收性能.进一步研究表明,当Au壳层较薄时,可以获得具有可调光学性能的壳核纳米结构;而当Au壳层较厚时,其光学性能与同尺寸单质Au微粒一致.通过计算分析,本文还将Mie理论推广到具有空腔结构并且壳层厚度达到一定值的纳米微粒.另外,研究发现合金结构纳米微粒的吸收峰位置与合金成分有着线性关系.本研究表明,人们可以通过控制纳米微粒的尺寸、形貌和结构,调节其表面等离子体共振峰位,这大大拓展了纳米微粒的应用范围.     

核壳结构CdS/ZnS纳米微粒的制备与光学特性

用微乳液法制备CdS纳米微粒 ,以ZnS对其进行表面修饰 ,得到具有核壳结构的CdS/ZnS纳米微粒 .采用X射线衍射 (XRD)、透射电镜 (TEM )表征其结构、粒度和形貌 ,紫外 可见吸收光谱 (UV)、光致发光光谱(PL)表征其光学特性 .制得的CdS近似呈球形 ,直径为 3.3nm ;以XRD和UV证实了CdS/ZnS核壳结构的实现 .研究了不同ZnS壳层厚度对CdS纳米微粒光学性能的影响 ,UV谱表明随着壳层厚度的增加纳米微粒的吸收带边有轻微的红移 ,同时短波吸收增强 ;PL谱表明壳层ZnS的包覆可减少CdS纳米微粒的表面缺陷 ,带边直接复合发光的几率增大 ,具有合适的壳层厚度时发光效率大大提高 .     

Si衬底上插入SiO2膜对Ag纳米颗粒陷光性能的影响

采用磁控溅射法在Si衬底上制备了SiO2介质膜,系统地研究了SiO2膜引入对Ag纳米颗粒的表面覆盖率、形貌、形成机理和光学性质的影响.研究发现引入SiO2介质膜后,Ag纳米颗粒的表面覆盖率显著增加,平均粒径明显降低.基于现有的Ag纳米颗粒形成机理,提出了粗糙表面Ag膜断裂模型以解释其形貌发生变化的原因.紫外-可见光分光光度计测试表明,引入SiO2膜并优化其厚度,可使Ag纳米颗粒的偶极消光峰最大红移86nm,但消光峰强度明显下降.数值模拟计算表明,引入SiO2膜的Ag纳米颗粒所能散射的光子数量最小减少2×1018个.因此,在Si衬底上沉积SiO2膜,不利于Ag纳米颗粒陷光性能的提高.     

A facile and flexible process of β-cyclodextrin grafted on Fe3O4 magnetic nanoparticles and host-guest inclusion studies

In this study, a kind of novel surface-functionalized magnetic nanoparticles was fabricated by the Fe₃O₄ nanoparticles surface modification with mono-6-deoxy-6-(p-tolylsulfonyl)-cyclodextrin (6-TsO-β-CD), which were employed to interact with uric acid and their behavior was investigated by electrochemical methods. The architecture has been characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA), which confirmed that cyclodextrins have been effectively functionalized on the surface of Fe₃O₄ nanoparticles. The analyses of vibration sample magnetometer (VSM) verified that the nanoparticles owned good magnetic property. The grafted β-cyclodextrin on the Fe3O4 nanoparticles contributed to as a modified electrode for detecting uric acid with cyclic voltammograms. Electrochemical results revealed that the new materials could exhibit excellent molecules recognition ability and show high electrochemical response. The new nanoparticles simultaneously had unique properties of magnetic nanoparticles and cyclodextrins through combining their individual distinct advantages.     

Sonochemical synthesis of silver vanadium oxide micro/nanorods: Solvent and surfactant effects

In this investigation, a facile sonochemical route has been developed for the preparation of silver vanadium oxide (SVO) micro/nanorods by using silver salicylate and ammonium metavanadate as silver and vanadate precursor, respectively. Here, silver salicylate, [Ag(HSal)], is introduced as a new silver precursor to fabricate AgVO₃ nanorods. The effect of numerous solvents and surfactants on the morphology and sonochemical formation mechanism of AgVO₃ nanorods was studied. AgVO₃ nanorods were characterized by SEM and TEM images, XRD patterns, FT-IR, XPS, and EDS spectroscopy. SEM, TEM, and XRD results showed that AgO nanoparticles were formed onto AgVO₃ nanorods in the presence of ethanol, cyclohexanol, dimethylsulfoxide (DMSO), and acetone. By using polyethylene glycol (PEG-6000) and N,N-dimethylformamide (DMF) as organic additives, the thickness of AgVO₃ nanorods decreased.     

Preparation and properties of nano-sized Ag and Ag2S particles in biopolymer matrix

Silver (Ag) and silver sulfide (Ag₂S) nanoparticles were synthesized in a sago starch matrix. The resulting nanocomposites were investigated using structural, optical and thermal methods. XRD spectra of the nanocomposites confirmed the presence of nanostructured silver (cubic phase) and silver sulfide (monoclinic phase) in the matrix. TEM micrographs showed that the nanoparticles are mostly spherical in shape. Analyzes of the optical properties of the silver nanocomposite aqueous dispersions/solutions of various concentrations were carried out. The results and the theoretical considerations suggested that at high concentrations there is a release of silver nanoparticles from the composite in the water environment. Further dilution produces homogeneous solution in which silver nanoparticles are capped with starch macromolecules. TGA analysis revealed reduced thermal stability of the nanocomposites with respect to pure starch matrix.     

A facile way for preparing tin nanoparticles from bulk tin via ultrasound dispersion

In this paper, we reported a facile and rapid process to prepare tin nanoparticles from bulk tin via ultrasound dispersion. The morphology and structure of synthesized tin nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and thermogravimetric analysis (TGA). The results show that the morphology of tin nanoparticles is spherical and the structure of tin nanoparticles has the same crystal structure as the bulk tin. In addition, the tribological property of tin nanoparticles as additives in oil is evaluated on a four-ball tester and the results show that tin nanoparticles exhibit good performance in wear.     

BSA-SDS-Ag聚合物纳米微粒的制备及其水凝胶性质的研究（Ⅰ）

报道了BSA－SDS－Ag聚合物纳米微粒的制备及水凝胶的性质,用X射线衍射（XRD）、透射电镜（TEM）、傅里叶变换红外（FT－IR）光谱考察了这种聚合物微粒的结构,微粒粒径32nm左右,用UV／Vis光谱及SEM考察了冰凝胶的性,表明Ag^ 离子先与BSA产生化学键合,再学原了Ag粒,进行聚合成网状结构的聚合物。     

Surface modification of magnesium aluminum hydroxide nanoparticles with poly(methyl methacrylate) via one-pot in situ polymerization

Hydrophobic magnesium aluminum hydroxide composite particles (PMMA-MAH) were obtained by means of grafting poly(methyl methacrylate) (PMMA) onto the surface of magnesium aluminum hydroxide(MAH) nanoparticles after a novel type of phosphate coupling agent (DN-27) modification. The introduction of functional double bonds was firstly conducted on the surface of nanoparticles by DN-27 modification, followed by one-pot in situ polymerization on the particles surface using methyl methacrylate (MMA) as monomer, azoisobutyronitrile (AIBN) as initiator and sodium dodecyl sulfate (SDS) as stabilizer to graft PMMA on the surface of DN-27-modified MAH particles. The obtained composite particles were characterized by field-emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD). The results show that the organic macromolecule PMMA could be successfully grafted on the surface of DN-27-modified MAH nanoparticles and the thermal stability of the PMMA-MAH composite particles had been improved. Compared with unmodified blank MAH sample, the product obtained with this method possesses better hydrophobic properties such as a higher water contact angle of 108° and a well dispersion.     

Surface-modification in situ of nano-SiO2 and its structure and tribological properties

The preparation of a series of dispersible nano-SiO₂ by surface-modification in situ was described in this paper. It is found that some silane coupling agents can be combined with nano-SiO₂ by covalent bonds, which change the nanoparticle's surface properties and make nano-SiO₂ disperse well and steadily in many organic mediums. The structure of nanoparticles was characterized by transmission electron microscopy (TEM), infrared spectrum (IR), X-ray photoelectron spectra (XPS) and thermogravimetric analysis (TG). The dispersivity of these nanoparticles in organic solvents was measured by light transmittance. Considering such superior dispersion in oily solvents and very small size, we primarily investigated their tribological behaviors as additive in lubricant on wear testers. The results show that they can evidently increase anti-wear ability and reduce the friction coefficient of lubricant.     

Preparation and tribological properties of stearic acid-modified hierarchical anatase TiO2 microcrystals

Hierarchical TiO₂ microcrystals were synthesized through a facile solvothermal method. X-ray diffraction (XRD) and scanning electron microscope (SEM) measurements were used to characterize the structure of the as-prepared samples. The results indicated that the synthesized hierarchical titania (TiO₂) microspheres were composed of numerous anatase phase TiO₂ particles. The as-prepared samples were chemically modified with stearic acid to improve their dispersion in oil. Fourier transmission infrared spectroscopy (FT-IR) and thermogravimetry analysis (TGA) were carried out to evaluate the characteristics of the modified TiO₂ microcrystals. The tribological properties of the modified TiO₂ microcrystals as additives of liquid paraffin were studied by a four-ball tester, and the results showed that they could significantly improve anti-wear performance, friction-reduction property and load-carrying capacity of liquid paraffin. These advantages make the modified TiO₂ microcrystals promising for green lubricating oil additives.     

Structural and spectroscopic studies of thin film of silver nanoparticles

We report the deposition of thin film of silver (Ag) nanoparticles by wet chemical method. The as-synthesized Ag nanoparticles have been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray energy dispersive spectroscopy (EDS), field emission transmission electron microscopy (FETEM) and high-resolution TEM (HRTEM), UV-vis spectroscopy and thermogravimetric-differential thermal analysis (TG-DTA) respectively. FESEM image indicates that the silver film prepared on the quartz substrate is smooth and dense. XRD pattern reveals the face-centered cubic (fcc) structure of silver nanoparticles. EDS spectrum indicates that samples are nearly stoichiometric. From TEM analysis, it is found that the size of high purity Ag nanoparticles is ranging from 10 to 20 nm with slight agglomeration. Absorption in UV-vis region by these nanoparticles is characterized by the features reported in the literature, namely, a possible Plasmon peak at ∼403 nm. Optical absorbance spectra analysis reveals that the Ag film has an indirect band structure with bandgap energy 3.88 eV. TGA/DTA studies revealed that a considerable weight loss occurs between 175 and 275 °C; and the reaction is exothermic.