Preparation of Polypyrrole/Poly(methyl methacrylate) Core-Shell Nanoparticles in Four-Component Microemulsion Media

Electrically conductive polypyrrole (PPy)/poly(methyl methacrylate) (PMMA) core-shell nanoparticles were synthesized by two-step microemulsion polymerization. PPy core particles were prepared in a four-component microemulsion system, which was formed with surfactant cetyltrimethyl ammonium bromide (CTAB), cosurfactant n-pentanol, water, and pyrrole. Ferric chloride and iodine was added as the oxidant and the dopant, respectively. Then the PPy nanoparticles were coated with PMMA to prepare PPy/PMMA core-shell nanoparticles. The morphology of PPy/PMMA core-shell nanoparticles was characterized with transmission electron microscopy (TEM). Fourier transform infrared (FTIR) spectroscopy was used to characterize the structure of the samples. The electrical conductivities of samples were studied by a Hall effect testing instrument. Despite being coated with a layer of insulation, the conductivity of the composite PPy/PMMA core-shell nanoparticles could still reached to 7.856 × 10^?1 S/cm.     

Fabrication of silica nanoparticles and hollow spheres using ionic liquid microemulsion droplets as templates

Silica products with two different morphologies were synthesized using nonaqueous ionic liquid microemulsion droplets as templates. The morphologies of the obtained products were characterized by both transmission electron microscopy (TEM) and scanning electron microscopy (SEM). By adjusting the reaction conditions, ellipsoidal nanoparticles were formed under acidic conditions, while hollow silica spheres were obtained under alkaline conditions. It is demonstrated that the size distribution of hollow silica spheres was narrower than that of the ellipsoidal nanoparticles. The various vibration modes of different functional groups in the silica materials were revealed by Fourier transform infrared (FTIR) spectroscopy. The two samples were both shown to be amorphous, not crystalline by X-ray diffraction (XRD). A simple diagram of the formation process including the hydrolysis and condensation reactions is given. Furthermore, a probable mechanism for the formation of silica materials under acidic or alkaline conditions is presented, which may be helpful for better understanding the different silica materials obtained under different conditions.     

Modification of the Stöber process by a polyazamacrocycle leading to unusual core-shell silica nanoparticles

In the view of designing functional nanoparticles, the encapsulation of 1,4,7,10-tetraazacyclododecane (cyclen) within silica nanoparticles using the St?ber process was studied. In the presence of cyclen and tetraethoxysilane (TEOS), silica particles exhibiting an unusual core-shell structure were obtained. On then basis of TEM, DLS, and NMR data, we suggest that the particle core is constituted of hybrid primary nanoparticles resulting from cyclen-silica interactions, whereas the shell formation results from further condensation of unreacted silica precursors. Control experiments performed with the zinc-cyclen complex and ammonia addition suggest that cyclen-TEOS interactions arise from the activation of the silicon alkoxide hydrolysis with the polyazamacrocycle amine groups. These data are discussed in the context of silica biomineralization mechanisms, where polyamine/silica interactions have been shown to play a major role. Moreover, the possibility to control the size and the structure of these nanoparticles makes them promising materials for pharmaceutical applications.     

Co@SiO2核壳式纳米磁性粒子的合成、性质表征及在细胞分离和细胞芯片上的应用

合成了Co@SiO2核壳式纳米粒子,并采用透射电镜(TEM)、X射线衍射(XRD)、扫描电镜(SEM)和振动样品磁强计(VSM)对其形状、尺寸、荧光及磁特性进行了表征,探讨了其在细胞分离和细胞芯片上的应用和原理.     

Co@SiO2核壳式纳米粒子的合成、性质表征及在细胞分离和细胞芯片上的应用

合成了Co@SiO2核壳式纳米粒子, 并采用透射电镜(TEM)、 X射线衍射(XRD)、扫描电镜(SEM)和振动样品磁强计(VSM)对其形状、尺寸、荧光及磁特性进行了表征, 探讨了其在细胞分离和细胞芯片上的应用和原理.     

Formation of organically and inorganically passivated CdS nanoparticles in reverse microemulsions

This paper is focused on the formation of organically and inorganically passivated cadmium sulfide (CdS) nanoparticles in two different types of microemulsions. On the one hand, we used a ternary inverse microemulsion consisting of water, heptanol, and 3-(N,N-dimethyldodecylammonio)propanesulfonate and on the other hand, a poly(ethyleneimine)-based quaternary microemulsion containing water, toluene, pentanol, and sodium dodecylsulfate. UV-vis measurements confirm the formation of CdS-ZnS core-shell nanoparticles in the ternary microemulsion. Using the quaternary microemulsion template phase, polymer capped luminescent CdS nanoparticles can be formed. After a complete solvent evaporation, the nanoparticles are redispersed in water and characterized by means of dynamic light scattering and transmission electron microscopy. From the ternary microemulsion, well-stabilized CdS-ZnS core-shell nanoparticles with diameters of about 5 nm can be redispersed, but from the quaternary microemulsion, only nanoparticle aggregates of about 100 nm.     

Novel Synthesis of CeO2 Nanoparticles Within Formamide/Tri(ethyleneglycol)monododecyl Ether/n-Octane Nonaqueous Microemulsion Systems

The present study evaluates a new method to prepare Cerium oxide (CeO₂) nanoparticles by formamide/tri(ethyleneglycol)monododecyl ether (C₁₂E₃)/n-octane oil-continuous nonaqueous microemulsion. The effect of the polar phase (formamide/water) on the phase behavior, drop size, and conductivity behavior of the reverse microemulsion were investigated. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the phase and morphology of synthesized CeO₂ nanoparticles. It was found that the CeO₂ powders synthesized within nonaqueous microemulsions and aqueous microemulisons had an average particle size of 30–50 nm and 15–40 nm, respectively. The experimental results indicate the formation mechanism of CeO₂ nanoparticles in formamide nonaqueous microemulsion and aqueous microemulsion is similar, and the formamide nonaqueous microemulsion can be used as nanoreactors for preparation of nanoparticles.     

TEM-induced structural evolution in amorphous Fe oxide nanoparticles

Exposure to the high energy electron beam of a TEM changes the morphology of amorphous Fe oxide nanoparticles from solid spheres to hollow shells. Amorphous Fe oxide nanoparticles prepared via high-temperature methods using hexadecylamine and trioctylphosphine oxide surfactants were compared to crystalline gamma-Fe2O3 particles of similar size. Both sets of particles are fully characterized via SQUID magnetometry, X-ray powder diffraction, BET surface analysis, EPR spectroscopy, high-resolution transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). Time-resolved TEM images reveal that the amorphous Fe oxide particles evolve from solid spheres into hollow shells in <2 min, whereas crystalline gamma-Fe2O3 are unaffected by the electron beam. The resulting nanocrystalline Fe oxide shells bear striking resemblance to core-shell nanocrystals, but are a result of a morphology change attributed to restructuring of particle voids and defects induced by quasi-melting in the TEM. These results thus imply that caution is necessary when using TEM to analyze nanoparticle core-shell and heterostructured nanoparticles.     

反相微乳液法制备纳米SiO2的研究

在壬基酚聚氧乙烯5醚(NP-5)/环己烷/氨水的反相微乳液体系中，进行正硅酸乙酯(TEOS)的水解、缩合反应，得到粒径在30～50 nm的单分散纳米SiO₂胶体。红外光谱法(FTIR)及透射电子显微镜(TEM)观察证明了纳米SiO₂粒子的生成。反相微乳液体系相图的研究表明，水相为氨水比纯水有较窄的W/O型微乳区。氨水微乳液是碱催化TEOS水解、缩合制备纳米SiO₂粒子的适宜体系。当体系中TEOS的浓度增大时，粒子的粒径随之增大。降低NP-5     

吲哚类菁染料Cy3嵌入的核壳荧光纳米颗粒的制备及其性质研究

以蛋白质或多肽修饰的吲哚类菁染料Cy3为内核, 采用实验条件简单的油包水反相微乳液方法成核, 通过正硅酸乙酯水解形成的网状二氧化硅包壳的方法制备吲哚类菁染料Cy3嵌入的核壳荧光纳米颗粒. 考察了以不同等电点的蛋白质和多肽修饰的Cy3为内核材料对吲哚类菁染料Cy3嵌入的核壳荧光纳米颗粒制备的影响. 结果表明, 分别采用人免疫球蛋白(IgG)或多聚赖氨酸修饰的Cy3为内核材料, 都能制备荧光强度高、荧光稳定性强和染料泄漏极少的Cy3嵌入的核壳荧光纳米颗粒. 进一步对Cy3嵌入的核壳荧光纳米颗粒进行了表征, 并将基于这一新型的荧光纳米颗粒建立起来的生物标记方法初步应用于流感病毒DNA的检测, 其检测线性范围为3.18×10-10～1.27×10-9 mol/L, 检测下限为3.51×10-10 mol/L, 相关系数r为0.986 5.     

SiO2@Fe2O3核-壳结构催化剂的制备及表征

采用优化的Stöber法制备了平均粒径为230 nm的单分散球形SiO₂颗粒,并以此为内核,通过水解沉积法制备了不同壳层厚度的核-壳结构SiO₂@Fe₂O₃催化剂。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、N₂物理吸附和X射线衍射分析(XRD)等手段对催化剂进行表征,探讨了不同制备条件对SiO₂@Fe₂O₃催化剂形貌的影响。结果表明,通过水解沉积法制备的SiO₂@Fe₂O₃催化剂具有明显的核-壳结构,并且保持了原始SiO₂核的球形形貌,Fe₂O₃纳米粒子通过-OH的氢键作用连接在SiO₂表面,形成了2~10 nm厚的Fe₂O₃均匀连续包覆层。     

嵌合异硫氰酸罗丹明B核壳荧光纳米颗粒制备的新方法研究

随着纳米技术的发展,结合了纳米技术与材料制备技术而发展起来的荧光染料嵌合的核壳荧光纳米颗粒的制备为生物医学领域的研究提供了新的材料、技术和方法。何晓晓等以联钉吡啶配合物为核材料,制备了嵌合无机金属配合物的核壳荧光纳米颗粒,段菁华等用异硫氰酸荧光素FITC与蛋白质IgG相结合,     

核-壳结构的氯化银/聚丙烯酰胺复合纳米粒子的制备与表征

用反相微乳液作为模板制备了核-壳结构的氯化锯／聚丙烯酰胺(AgCI／PAM)复合纳米粒子。透射电镜(TEM)证实复合粒子为核-壳结构，平均直径约100nm。扫描电子显微镜(SEM)和X射线衍射分析显示，平均粒径约50nm的AgCl均匀分散在聚合物中。FTIR谱图表明：AgO与PAM之间存在较强的相互作用。用能级探洲光谱(Energy Detected Spectrum，EDS)和润湿分散实验比较了不同方法改性的复合粒子的表面结构与润湿性能。     

Magnetite nanoparticles with tunable gold or silver shell

Fe3O4 nanoparticles with size approximately 13 nm have been prepared successfully in aqueous micellar medium at approximately 80 degrees C. To make Fe3O4 nanoparticles resistant to surface poisoning a new route is developed for coating Fe3O4 nanoparticles with noble metals such as gold or silver as shell. The shell thickness of the core-shell particles becomes tunable through the adjustment of the ratio of the constituents. Thus, the route yields well-defined core-shell structures of size from 18 to 30 nm with varying proportion of Fe3O4 to the noble metal precursor salts. These magnetic nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), FTIR, differential scanning calorimetry (DSC), Raman and temperature-dependent magnetic studies.     

A new ion-exchange adsorbent with paramagnetic properties for the separation of genomic DNA

A new ion-exchange adsorbent (IEA) derived from Fe(3)O(4)/SiO(2)-GPTMS-DEAE with paramagnetic properties was prepared. Fe(3)O(4) nanoparticles were firstly prepared in water-in-oil microemulsion. The magnetic Fe(3)O(4) particles were modified in situ by hydrolysis and condensation reactions with tetraethoxysilane (TEOS) to form the core-shell Fe(3)O(4)/SiO(2). The modified particles were further treated by 3-glycidoxypropyltrimethoxysilane (GPTMS) to form Fe(3)O(4)/SiO(2)-GPTMS nanoparticles. Fe(3)O(4)/SiO(2)-GPTMS-DEAE nanoparticles (IEA) were finally obtained through the condensation reaction between the Cl of diethylaminoethyl chloride-HCl (DEAE) and the epoxy groups of GPTMS in the Fe(3)O(4)/SiO(2)-GPTMS. The obtained IEA has features of paramagnetic and ion exchange properties because of the Fe(3)O(4) nanoparticles and protonated organic amine in the sample. The intermediates and final product obtained in the synthesis process were characterized. The separation result of genomic DNA from blood indicated that Fe(3)O(4)/SiO(2)-GPTMS-DEAE nanoparticles have outstanding advantages in operation, selectivity, and capacity.     

反相微乳液介质中纳米Sm2O3的制备

用十六烷基三甲基溴化铵(CTAB)/正丁醇/正辛烷/钐盐水溶液(氨水)所形成的反相微乳液体系, 控制合成Sm2O3球形纳米粒子. 绘制出25 ℃下CTAB/正丁醇/正辛烷/钐盐水溶液(氨水)体系的拟三元相图, 得到了反相微乳液区.在此反相微乳区内合成了Sm2O3的前驱体, 对前驱体进行热分析(TG-DSC), 确定了得到纳米Sm2O3产物的适宜焙烧温度为900 ℃, 并考察了微乳液中反应物浓度、反应时间等因素对合成产物的影响. 采用X射线衍射(XRD)、透射电镜(TEM)、激光粒度仪(NSA)、荧光光谱(FS)仪等分析方法对Sm2O3产物的形貌、晶形、粒径及荧光性质进行了表征. 结果表明, 25 益下利用反相微乳液法, 成功地制备了粒径分布较窄、分散性良好的球形纳米Sm2O3粒子, 粒径约20 nm左右, 且表现出较强的荧光性质.     

真空冷冻干燥制备高比表面积纳米氧化铝

采用真空冷冻干燥技术结合反相微乳液法, 于环己烷/聚乙二醇辛基苯基醚(曲拉通X-100)-十六烷基三甲基溴化铵(CTAB)/正丁醇/水溶液体系中, 合成了纳米Al2O3粉体. 采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)及比表面积与孔隙度分析仪对产物的形貌、结构、比表面积、孔容与孔径进行了表征. 经过煅烧, 该纳米Al2O3比表面积约550.0 m2·g-1(随反应参数不同而变化), 属γ-Al2O3晶型, 粒径均匀, 颗粒直径小于10.0 nm. 考察了不同的干燥方式(电热鼓风干燥、普通真空干燥、真空冷冻干燥)以及真空冷冻干燥过程中主要参数对产物比表面积、孔容、平均孔径等物理性质的影响. 结果表明, 采用真空冷冻干燥法制备的纳米Al2O3的比表面积和孔容远高于采用另外两种干燥方式制备的纳米Al2O3. 采用真空冷冻干燥法制备纳米Al2O3时, 降温速率、预冻时间、冻干时间等参数对最终制备的产物比表面积与孔结构有显著影响.     

琥珀酸二异辛酯磺酸钠微乳体系中纳米银的制备及其连续相的影响

在琥珀酸二异辛酯磺酸钠(AOT)为表面活性剂、环己烷为连续相形成的微乳体系中, 利用水合肼还原AgNO₃制备了分散性良好的纳米银. 利用紫外-可见(UV-Vis)光谱和透射电镜(TEM)对所得产物进行了表征, TEM显微图像表明形成粒子为球形结构, 平均粒径为5.10 nm, 标准偏差为2.84 nm. 分别利用正己烷、正庚烷、正辛烷、环己烷和十二烷等作连续介质, 研究了微乳液中连续相对纳米银形成的影响. 随着正烷烃碳链长度的增加, 微乳液中胶束之间的交换速率增大, 形成粒子的平均粒径逐渐减小. 十二烷形成的微乳体系制备的纳米银溶胶具有最宽的共振吸收峰, 所得的纳米银粒子平均粒径最小. 环己烷形成的微乳液中反胶束具有特殊的界面强度, 导致纳米银晶核的形成速率过低, 纳米银晶粒的生长不完全.     

Ru(bpy)_3 掺杂的核壳型 Ag@SiO_2 荧光纳米粒子的制备及表征

利用反相微乳液法制备了一种三联吡啶钌掺杂的核壳型Ag@SiO2纳米粒子。利用透射电子显微镜、荧光光谱和紫外-可见光谱等对其进行表征,并对其光稳定性和表面氨基进行了测定,结果表明该纳米粒子单分散性良好,呈规则球状、粒径为(60±5)nm,由于银的金属增强荧光效应,相对没有银核的Ru(bpy)3掺杂的SiO2纳米粒子,其荧光强度增强了2倍,光稳定性也有所提高。     

Synthesis of Octylmethoxycinamate-silica Core-shell Nanoparticles with Self-templating Method

A self-templating method was employed to synthesize core-shell nanoparticles with octylmethoxycinamate(OMC), a well-known organic UV absorber, as core and nanosilica particles as shell. The characteristic of this method is that the whole process requires neither surface treatment for nanosilica particles nor additional surfactant or stabilizer, and all the reactions could be finished in one-pot, which exempts removing template and reduces reaction steps compared to the conventional process. The morphology, structure, particle size distribution, chemical composition and optical property of OMC-SiO2 nanoparticles were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), dynamic light scattering(DLS), FTIR spectrometry and UV absorption spectrometry, respectively. Experiment results indicate that the resulting OMC-SiO2 nanoparticles were perfectly spherical with smooth particle surfaces, and had clear core-shell structures. The particle size could be tuned by altering reaction conditions. In addition, the mechanism of the self-templating method for forming core-shell nanoparticles was discussed.