Fe_3O_4/Au复合磁性纳米颗粒的制备及其表征

首先通过化学共沉淀法制备出Fe3O4磁性纳米颗粒,考察了表面活性剂的用量、碱的用量、陈化时间以及三价铁与二价铁的摩尔比等因素对Fe3O4纳米颗粒性能的影响。制备出饱和磁化强度为73.85A.m2/kg、粒径大小为10nm以下的Fe3O4纳米颗粒。在此基础上,制备出Fe3O4/Au复合纳米颗粒,通过VSM、TEM、XRD、XPS对产物进行了表征,研究了HAuCl4的用量、还原剂的种类、硅烷偶联剂以及包金之前的Fe3O4纳米颗粒对复合颗粒的影响,结果表明所制得的Fe3O4/Au复合磁性纳米颗粒包覆良好,粒径大小为50～200nm,饱和磁化强度为10.08A.m2/kg。     

纳米尺度PS/Ag核壳结构复合球的制备与表征

采用分步法制备了聚苯乙烯/银(PS/Ag)核壳结构复合纳米球。首先采用无皂乳液聚合法并利用丙烯酸(AA)的羧基对制备的PS球进行改性,使其表面带负电荷;然后通过静电吸附作用在改性PS球的表面沉积[Ag(NH3)2]+,水浴(80℃)环境中利用十二烷基磺酸钠(SDS)作为还原剂将PS球表面的[Ag(NH3)2]+还原,制备出PS/Ag核壳结构复合球。通过动态激光粒度分析仪和透射电子显微镜对PS/Ag核壳纳米球的粒度分布、形貌和结构进行了表征,研究了AA的用量对复合球粒径及包覆的Ag壳厚度的影响。结果表明,随着AA用量的增大,所包覆的银层更加致密,厚度增大,当AA用量为15%时可得到Ag完全包覆的PS/Ag复合纳米球。     

核壳结构纳米颗粒的研究进展

核壳结构纳米颗粒具有不同于核和壳的物理和化学性能，通过调整核和壳的化学组成、尺寸和形貌，可以调控纳米颗粒的性能，扩展纳米颗粒的应用范围。系统总结了近年来制备核壳结构纳米颗粒的研究进展，讨论了核壳结构纳米颗粒对光学特性的影响。     

金/银合金纳米颗粒的制备及光学吸收特性

以柠檬酸盐为还原剂,通过共还原氯金酸和硝酸银的混合溶液制备出Au／Ag合金纳米颗粒,用透射电子显微镜（TEM）对颗粒的形貌和尺寸进行了表征。300-800nm范围的吸收光谱研究发现,Au／Ag合金纳米颗粒具有单峰等离子体吸收特征,且随着反应液中氯化金和硝酸银的摩尔比的减少,吸收峰将产生蓝移。实验结果表明,Au-Ag合金纳米颗粒的光学吸收特性具有组分可裁剪性,使其在纳米尺度的光学领域具有潜在的应用价值。     

核壳结构纳米颗粒的研究进展

核壳结构纳米颗粒具有不同于核和壳的物理和化学性能,通过调整核和壳的化学组成、尺寸和形貌,可以调控纳米颗粒的性能,扩展纳米颗粒的应用范围.系统总结了近年来制备核壳结构纳米颗粒的研究进展,讨论了核壳结构纳米颗粒对光学特性的影响.     

碳包裹镍核-壳结构复合纳米颗粒的制备及性能研究

采用自行研制的实验装置,通过阳极弧放电等离子体技术成功制备了碳包裹镍核-壳结构纳米复合颗粒,并采用酸洗和磁选的方法对初产物进行了纯化.利用高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)、透射电子显微镜(TEM)和X射线能量色散分析谱仪(XEDS)等测试手段对样品的化学成分、形貌、微观结构和粒度等特征进行了表征...     

SiO2／Ag核壳复合粒子的制备与表征

首次引入活性SiO2微球作为核基，采用自组装液相还原技术，定向的在核基上沉积纳米银颗粒得到SiO2／Ag核壳复合粒子；并用红外、x射线衍射、场发射扫描电镜、能谱等分析表征该核壳复合粒子的形貌与结构。结果表明：利用活性SiO2作为核基，pH值为12．4，有表面活性剂参与的条件下，通过改变银前驱体浓度，可实现表面包覆致密、银壳厚度可控的核壳复合粒子化学制备技术。     

交联β-环糊精聚合物/Fe3O4核壳结构复合纳米颗粒的制备和性能研究

以羧甲基-β-环糊精为表面修饰剂对Fe3O4纳米粒子进行包覆修饰,以环氧氯丙烷为交联剂,在β-环糊精的碱性溶液中通过Fe3O4纳米粒子表面进行的交联反应制备了交联β-环糊精聚合物/Fe3O4复合纳米颗粒.利用FTIR、XRD、TEM和TGA分剐对复合纳米颗粒的结构、形貌和尺寸进行了表征.结果表明,制备的复合纳米颗粒为近球形、核壳结构,粒径约为10～20nm,环糊精聚合物含量为29%,在水中的分散性良好.磁性能测试和包合性能测试表明,复合纳米颗粒为超顺磁性,对特定分子具有一定的包合能力,可用于靶向给药系统和特定物质分离的载体.     

Ag纳米晶颗粒/碳纳米管复合材料的制备与结构研究

利用热蒸发方法在多壁碳纳米管表面沉积Ag纳米颗粒,XRD结果显示,Ag纳米颗粒以晶体形态存在,同时透射电镜分析结果表明,Ag纳米晶颗粒引起碳纳米管横截面形变,从而形成Ag纳米晶颗粒/碳纳米管异质复合材料,这些纳米异质复合材料相互连接,形成网络化分布的结构.     

核壳结构Co/SiO_2非晶态纳米颗粒的制备和性能

主要研究了核壳结构Co/SiO2非晶态纳米颗粒的制备及性能。正硅酸乙酯水解生成二氧化硅,水溶液中硼氢化钠还原氯化钴生成钴单质,存在硅烷偶联剂APS时,将二者进行结合生成二氧化硅包覆在钴颗粒表面。采用XRD、TEM、FT-IR、VSM等手段对样品进行表征。     

Synthesis process of gold nanoparticles in solution plasma

We describe the dynamics of the synthesis of gold nanoparticles by a glow discharge in aqueous solutions. A pulsed power supply was used to generate discharges in the aqueous solutions. The initial [AuCl₄]⁻ ion concentration and the voltage applied between the electrodes were varied. The [AuCl₄]⁻ ion was reduced by the H radicals generated in the discharge. The reduction rates were calculated from the changes in the [AuCl₄]⁻ ion concentration during the discharge time. Dendrite-shaped nanoparticles of about 150 nm size were formed in discharge during 1 min. The pH of the solution decreased gradually with the increase of the discharge time. The decrease in pH led to the dissolution of gold nanoparticles. The reduction and the dissolution rates increased proportionately with the applied voltage. The size of the gold nanoparticles decreased at 20 nm after running the discharge during 45 min. Moreover gold nanoparticles with exotic shapes, such as triangle, pentagon, and hexagon were also observed. The particles were confirmed to be as polycrystalline gold nanoparticles by electron diffraction patterns. In summary, when the reduction rate lowered as a result of dissolution, anisotropic nanoparticles were formed and continued to grow in size in the solution.     

One-step high-yield aqueous synthesis of size-tunable multispiked gold nanoparticles

Multispiked gold nanoparticles are required in large quantities for many fundamental studies and applications like (bio)sensing, but their preparation in high yield by the bottom-up chemical synthetic method is challenging. A water-based, non-'seed-mediated', straightforward method for the synthesis of gold nanoparticles with well-developed surface spikes is reported here. The yield of multispiked gold particles is very high (>90%). The method allows the tuning of the number and size of the spikes and the overall size of the particles, and hence the localized surface plasmon resonances of the particles over the broad spectral range in the visible and near-infrared. A mechanism for the evolution of twinned, sharp-tipped surface protrusions has been proposed based on systematic spectrophotometric and transmission electron microscopic studies, which were employed to elucidate the morphological features, structure, chemical composition, and optical properties of the multispiked gold nanoparticles.     

膨胀蛭石/聚(丙烯酸钾-丙烯酰胺)高吸水性复合材料的制备、性能及表征

以N,N'-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,丙烯酸和丙烯酰胺为单体,采用新型水溶液聚合法合成了膨胀蛭石/聚(丙烯酸钾-丙烯酰胺)高吸水性复合材料.考察了交联剂用量、引发剂用量、单体浓度、中和度、反应温度、单体质量比及膨胀蛭石含量对吸水倍率的影响,试验结果表明,当蛭石含量为30%(相对单体质量,下同)时,交联剂用量为0.04%,引发剂为1.1%,中和度为75%(相对丙烯酸物质的量),单体浓度为50%,反应温度为75℃,吸水倍率最高可达1048g/g.最后,采用SEM、IR对其结构及组成进行了表征.     

Preparation of continuous gold nanowires by electrospinning of high-concentration aqueous dispersions of gold nanoparticles

Gold nanowires are prepared by the electrospinning of highly concentrated aqueous dispersions of gold nanoparticles (AuNPs) in the presence of poly(vinyl alcohol) and subsequent annealing at higher temperatures. Continuous wires of sintered AuNPs are obtained as a result of this process. The Au wires are characterized by transmission electron microscopy, helium ion microscopy, optical microscopy, and X-ray diffractometry.     

Development and evaluation of fluorescent gold nanoparticles

Objective: It is difficult to identify the gold nanoparticles (AuNPs) intracellularly due to their non-fluorescent nature. Although gold can quench the fluorescence of any fluorophore, hence it is also difficult to combine gold with a fluorophore such as a semiconductor quantum dots (QDs). The aim of this study was to prepare a single fluorescent stable AuNPs combined with QDs (QDs-Au-NPs) which can be easily detected intracellularly.

Methods: QDs-Au-NPs were prepared via a simple one-step process through controlling the spacing between them using polyethylene glycol (PEG) as space linker in the form of PEGylated QDs. Furthermore, the applicability of this system was evaluated after coating the particles with somatostatin citrate, SST, to active target somatostatin receptors (SSTRs), and identification of the internalized particles via confocal laser scanning spectroscopy.

Results: The results showed that the produced Au shell has a thickness of 2.0?±?0.2?nm and QDs-Au-NPs showed the same fluorescence intensity compared to the unmodified QDs. Additionally, a stable monodisperse QDs-Au-NPs coated with SST were prepared after coating with 11-Mercaptoundecanoic acid. Moreover, cellular uptake study in Human Caucasian breast adenocarcinoma cell lines showed that QDs-Au-SST-NPs could be detected easily using the confocal microscope. In addition, they showed a significant (p?≤?.05) internalization per cell compared to untreated QDs-Au-NPs as detected by flow cytometry.

Conclusion: It could be concluded that the produced QDs-Au-NPs has a strong fluorescence property like QDs which enable them to be easily detected after cells internalization.     

次亚磷酸钠还原法制备纳米铜颗粒

利用液相还原两步法,油酸为萃取荆和保护剂,葡萄糖和次亚磷酸钠将五水硫酸铜分别还原为氧化亚铜和单质铜,制备得到了粒度为50～100nm左右分散均匀的球形纳米铜颗粒,并用XRD、SEM和TEM对其进行了表征.结果表明,在油酸的保护下,采用液相还原两步法可制得分散性好、具有抗氧化性能的球形纳米铜颗粒.     

一种新颖的硅量子点-金复合纳米粒子的制备和表征

利用电化学刻蚀法制备的硅量子点的还原特性,通过调整硅量子点与氯金酸的量的比例,可控合成了包含有不同尺寸金纳米颗粒的复合纳米粒子,并通过实验证明了硅量子点与金纳米颗粒的结合。在电化学刻蚀制备硅量子点的同时,通过微波辅助法可以迅速地在硅量子点表面有效地修饰上一部分羧基、羟基或者烷基链,从而间接预先对这种复合纳米粒子进行修饰。这种新型的纳米复合材料具有硅量子点的荧光性质的同时,还具有各种尺寸纳米金的光学性质,具有广阔的应用前景和研究价值。     

纳米金/单壁碳纳米管复合物的制备、表征及其多相催化的潜力

制备了一种单壁碳纳米管担载金纳米颗粒复合材料,利用X射线衍射、扫描透射显微镜、能量色散X射线分析、比表面积分析、激光拉曼光谱和紫外-可见分光光度计等对其结构进行了表征.结果表明:纳米金粒为微晶体,其平均直径为7nm且直径分布范围较窄.研究了该单壁碳纳米管担载金颗粒对仲醇的无溶剂氧化的活性和选择性,发现其转化效率可达95％.