A simple route to disperse silver nanoparticles on the surfaces of silica nanofibers with excellent photocatalytic properties

In this work, monodispersed silver nanoparticles decorated SiO₂ nanofibers were synthesized by electrospinning method, followed by thermal treatment at 600 °C. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermo-gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) were used to characterize the composite nanofibers. Accordingly, the detailed formation mechanism of SiO₂/Ag composite nanofibers was discussed. Furthermore, an excellent catalytic activity of SiO₂/Ag composite fibers was observed by a degradation reaction of methyl orange (MO) dye.     

A simple route to platinum and Pt-based composite nanotubes

Platinum (Pt) and Pt-based composite nanotubes were fabricated by a facile dipping method within alumina templates. The morphology, structure, and composition of the nanotubes were characterized by SEM, TEM, and EDX. A hydrogen sensor based on Pt/TiO2 composite nanotubes showed high hydrogen sensitivity.     

A simple route to large-scale production of tungsten trioxide nanoparticles

Tungsten trioxide particles in high yield were prepared via a simple solid evaporation route with ammonium paratungstate hydrate as precursor and Ar gas as carrier gas. Detailed characterization by scanning electron microscopy has shown that increasing carrier gas flow rate promotes morphological evolution from large and irregular semi-spherical particles to non-agglomerated quasi-spherical particles, and finally to single-crystalline nanoparticles with an average diameter of 60 nm. The adsorption activity of the tungsten trioxide particles is size-dependent and increased with decreasing particle size. The present method could readily produce large-scale tungsten trioxide nanoparticles with ideal adsorption performance, and can be utilized to fabrication of various semiconductor oxides with advanced properties.     

共混与同轴静电纺载药纳米纤维的制备、表征及比较

采用共混和同轴静电纺制备了负载盐酸四环素药物的聚乙烯醇-苯乙烯吡啶盐(PVA-SbQ)/玉米醇溶蛋白(Zein)复合纳米纤维,在紫外光照射下得到光交联载药PVA-SbQ/Zein复合纳米纤维。利用扫描电镜(SEM)对不同纤维的形貌和直径分布进行了分析;采用透射电镜(TEM)对不同静电纺丝法制备的纳米纤维结构进行了观察和比较;强力测试表明同轴静电纺丝制备的纳米纤维力学性能更强;傅里叶变换红外光谱(FT-IR)曲线表明载药PVA-SbQ/Zein复合纳米纤维保持了原有的化学功能基团;最后比较了两种方法制备的载药纳米纤维膜的药物释放行为。     

A simple and general route for monofunctionalization of fluorescent and magnetic nanoparticles using peptides

Nanoparticles are now utilized in many diverse biological and medical applications. Despite this, it remains challenging to tailor their surface for specific molecular targeting while maintaining high biocompatibility. To address this problem, we evaluate a phytochelatin-related peptide surface coating to produce functional and biocompatible nanoparticles (NPs) based on fluorescent InP/ZnS and CdSe/ZnS or superparamagnetic FePt and Fe(3)O(4). Using a combination of transmission electron microscopy, size-exclusion chromatography and gel electrophoresis (GE), we demonstrate the excellent colloidal properties of the peptide-coated NPs (pNPs) and the compact nature of the coating (～4?nm thickness). We develop a simple protocol for the monofunctionalization of the pNPs with targeting biomolecules, by combining covalent conjugation with GE purification. We then employ functionalized InP/ZnS pNPs in a live-cell, single-molecule imaging application to specifically target and detect individual proteins in the cell membrane. These findings showcase the versatility of the peptides for preparing compact NPs of various compositions and sizes, which are easily functionalized, and suitable for a broad range of biomedical applications.     

Electrospun polyvinyl alcohol/chitosan composite nanofibers involving Au nanoparticles and their in vitro release properties

Au nanoparticles (Au NPs) containing polyvinyl alcohol (PVA)/chitosan (CS) composite nanofibers were successfully prepared by a simple and effective method called electrospinning. Au NPs were firstly synthesized under a mild condition with CS as the reducing agent and stabilizer, followed by being mixed with PVA solution and then the resulting fibers were fabricated. The research indicated that Au NPs were indeed doped into the as-prepared fibers and the composite fibers well preserved Au NPs' unique optical characteristics. Additionally, with the adjustment of the weight ratios between PVA and CS, the diameter distribution and the morphology of the nanofibers were largely changed. In vitro drug release experiments demonstrated that the drug release rate can be conveniently controlled by changing the crosslink time.     

Novel route to polyaniline nanofibers from miniemulsion polymerization

A new synthesis approach for polyaniline (PANI) nanofibers with a yield of 95% was developed by using miniemulsion polymerization method. The nanofibers of 40 nm in diameter and 300 nm in length obtained had self-assembled to form a continuous conducting network, which induced a high conductivity of 1.23 S/cm. By investigating the morphologies and chemical structures of the PANI nanofiber by TEM, SEM, XRD, and FT-IR, a possible formation mechanism was proposed.     

A simple route to triethanolamine (TEA) and cysteine capped ZnSe nanoparticles

Water soluble triethanolamine (TEA) and cysteine capped ZnSe nanoparticles have been synthesized via simple solution based route. The method involves the reduction of selenium followed by the addition of the metal salt and capping group. The pH and metal salts were varied to study their effect on the optical properties and morphology of the particles. The as-synthesised ZnSe nanoparticles properties were studied by UV-Vis, photoluminescence, FTIR spectroscopy, powder X-ray diffraction, transmission electron microscopy (TEM) and high resolution TEM.     

A polymer-network gel route to oxide composite nanoparticles with core/shell structure

A modified polymer-network gel route has been developed to prepare oxide composite nanoparticles with core/shell structure. The core particles, which are prepared firstly using an acrylamide gel method, are dispersed in the solution of the shell material to form a uniform suspension, and then the suspension system is gelled by the polymerization of acrylamide. The gel is calcined to remove the organic phase, consequently leading to the coating of the shell material on the core particles. The versatility of this sol-gel method in preparing core/shell nanocomposites is evidenced by the example of MgO-coated La_0.67Ca_0.33MnO₃ system. The preparation process has been discussed in detail.     

A simple microwave-based route for size-controlled preparation of colloidal Pt nanoparticles

A simple route for the preparation of colloidal Pt nanoparticles is demonstrated. The formation of such colloids occurs in a single-step process, involving the direct microwave-based heat-treatment of an aqueous solution containing H₂PtCl₆ and 3-thiophenemalonic acid. In the synthesis, the particle size can be controlled by the molar ratio of the reactant agents.     

Growth of ZnO nanoparticles from nanowhisker precursor with a simple solvothermal route

Methods of preparing nanoparticles have long been a topic experiencing extensive investigation. Among those methods developed, using template or polymer and surfactant as capping reagents were often effective. However, obtaining nanoparticles in high amounts and high purity still remains an unresolved challenge. Here, a simple two-step solvothermal method without using any surfactant or coating reactant to prepare ZnO nanoparticles with high purity in large scale was developed. X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the as-prepared ZnO nanoparticles, and the formation process of the nanoparticles was discussed finally.     

A simple route to lanthanum hydroxide nanorods

This letter first describes a facile, low-cost, solution-phase approach to the large-scale preparation of lanthanum hydroxide single crystal nanorods at 60 °C without any template and surfactant. X-ray diffraction (XRD) shows that the nanorods are of pure hexagonal structure. The size and morphology of the products were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Lanthanum hydroxide single crystal nanorods are with diameters of approximately 20 nm and lengths of 150-200 nm. The processes of formation and decomposition for the as-prepared lanthanum hydroxide nanorods were discussed.     

Removal of oil from water using magnetic bicomponent composite nanofibers fabricated by electrospinning

In the present study, a magnetic nanofibrous composite mat composed of polystyrene (PS)/polyvinylidene fluoride (PVDF) nanofibers with selective incorporation of iron oxide (Fe₃O₄) nanoparticles (NPs) on/in PS was successfully prepared via a facile two-nozzle electrospinning process for oil-in-water separation. Field emission scanning electron microscopy and infrared spectroscopy showed the mats to be highly-porous in structure and confirmed the presence of the Fe₃O₄ NPs on/in the nanofibers. Both PS and PVDF nanofibers exhibited oleophilic and hydrophobic properties. The results showed improved mechanical properties when PVDF was added to the composite mat compared to the pristine PS mat. In addition, the incorporation of magnetic Fe₃O₄ NPs in the composite mat helps in the easy recovery of the mats after the oil-in-water sorption process. The composite mats showed good oil sorption capacity (35–46 g/g) and improved mechanical property. The present electrospun magnetic PVDF/Fe₃O₄@PS nanofibers could be potentially useful for the efficient removal of oil in water and recovery of sorbent material.     

Adsorption of acid dyes from aqueous solutions by the ethylenediamine-modified magnetic chitosan nanoparticles

The adsorption characteristics of Acid Orange 7(AO7) and Acid Orange 10 (AO10) from aqueous solutions onto the ethylenediamine-modified magnetic chitosan nanoparticles (EMCN) have been investigated. The EMCN were essentially monodispersed and had a main particle size distribution of 15-40 nm and saturated magnetization of 25.6 emu/g. The adsorption experiments indicated that the maximum adsorption capacity occurred at pH 4.0 for AO7 and pH 3.0 for AO10, respectively. Due to the small diameter and the high surface reactivity, the adsorption equilibrium of AO7 and AO10 onto the EMCN reached very quickly. Equilibrium experiments fitted well with the Langmuir isotherm model, and the maximum adsorption capacity of the EMCN at 298K was determined to be 3.47 mmol/g for AO7 and 2.25 mmol/g for AO10, respectively. Thermodynamic parameters such as enthalpy change (ΔH°), free energy change (ΔG°) and entropy change (ΔS°) were estimated and the results indicated that the adsorption process was spontaneous and exothermic. Furthermore, the EMCN could be regenerated through the desorption of the dyes in NH(4)OH/NH(4)Cl solution (pH 10.0) and could be reused to adsorb the dyes again.     

A simple route to prepare nanocrystalline titanium carbonitride

Nanocrystalline titanium carbonitride, TiC_0.7N_0.3, has been synthesized directly by a simple reaction route of TiCl₄ and C₃N₃C1₃ using sodium as the reductant at 600°C. The composition of the powders has been investigated by X-ray powder diffraction. Transmission electron microscopy image reveals that the average size of the obtained particles is about 30 nm.     

A simple route to ultra long SiC nanowires

SiC nanowires are prepared by pyrolysis of hexamethyldisilane (HMDS), at 1200 degrees C in a flowing Ar atmosphere. The length of the nanowires is in millimeter scale. Transmission electron microscopy observations indicate that the diameters of the SiC nanowires are in the range of about 8 to 120 nm, and that most of the nanowires have numerous stacking faults. The formation mechanism of the nanowires is proposed.     

一种简单的溶剂热法合成炭微球

利用一种简单的溶剂法合成炭微球.采用无水乙醇作为碳源和溶剂,以无水乙醇还原Ni(Ac)_2得到的Ni作为催化剂,最佳反应条件:温度500℃、时间48h.采用X-射线衍射仪(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)以及Raman光谱对样品的成分、晶体结构和形貌进行了分析.结果表明:产品为圆球形和纺锤形两种形貌的炭微球,圆球形炭微球直径为1μm～2μm,纺锤形炭微球直径为1μm～2μm,长度为3μm～6μm.此法简便易行,炭微球的产率高达95%以上,且具有较规则的形貌和窄的尺寸分布.     

A facile route to shape controlled CdTe nanoparticles

Hexadecylamine (HDA) capped CdTe nanoparticles have been synthesized using a facile hybrid solution based/thermolysis route. This method involves the reaction by the addition of an aqueous suspension or solution of a cadmium salt (chloride, acetate, nitrate or carbonate) to a freshly prepared NaHTe solution. The isolated CdTe was then dispersed in tri-octylphosphine (TOP) and injected into pre-heated HDA at temperatures of 190, 230 and 270 °C for 2 h. The particle growth and size distribution of the CdTe particles synthesized using cadmium chloride as the cadmium source were monitored using absorption and photoluminescence spectroscopy. The final morphology of the CdTe nanoparticles synthesized from the various cadmium sources was studied by transmission electron microscopy (TEM) and high resolution TEM. The cadmium source has an influence on the final morphology of the particles.     

Preparation and electrical characterization of polyamide-6/chitosan composite nanofibers via electrospinning

We report on the preparation and electrical characterization of polyamide-6/chitosan composite nanofibers. These composite nanofibers were prepared using a single solvent system via electrospinning process. The resultant nanofibers were well-oriented and had good incorporation of chitosan. Current-voltage (I-V) measurements revealed interesting linear curve, including enhanced conductivities with respect to chitosan content. The electrical conductivity of the polyamide-6/chitosan composite nanofibers increased with increasing content of chitosan which was attributed to the formation of ultrafine nanofibers. In addition, the sheet resistance of composite nanofibers was decreased with increasing chitosan concentration.