聚吡咯纳米线凝胶的模板制备及储能与电化学传感性能

以配位聚合物凝胶为模板, 构筑均一的聚吡咯纳米线网络, 聚合后经简单处理除去模板, 得到性能优异的聚吡咯凝胶. 结果表明, 模板法合成的聚吡咯凝胶为由均一纳米线组成的三维网络结构, 具有良好的力学性能、 较大的比表面积及优异的电化学特性, 在0.28 A/g电流密度下, 比电容可达450 F/g, 在2.8 A/g电流密度下充放电1000次, 比电容仍可保持88.6%. 聚吡咯纳米线网络凝胶经葡萄糖氧化酶负载后得到柔性传感电极, 对低浓度(0.2 mmol/L)的葡萄糖具有快速响应性能, 有望用于超级电容器及生物电化学传感器等领域.     

Linear nano-templates of styrene and maleic anhydride alternating copolymers

Poly(styrene-alt-maleic anhydride) (SMA) self-assembles in aqueous solution to form nanotube structures. These can be used as templates to linearly guide the growth of a secondary polymeric or inorganic material. Templates are made starting from a basic SMA solution, followed by slow pH decrease by dialysis against deionized water, until a 50% degree of protonation is reached. The nanotube structure is composed of multiple polymer chains, associating sideways by π-stacking to form the nanotube walls. The SMA templates were used to grow linear composites, which shows the applicability of the template properties and also confirms the nanotube association mechanism. Linear polymer composites were formed using this SMA template: pyrrole was polymerized, silver nitrate was reduced to silver and silver cyanide nanowires were grown.     

Reactive Template Synthesis of Polypyrrole Nanotubes for Fabricating Metal/Conducting Polymer Nanocomposites

Unique nanocomposites of polypyrrole/Au and polypyrrole/Pt hybrid nanotubes are synthesized employing polypyrrole (PPy) nanotubes as an advanced support by solution reduction. The conducting polymer PPy nanotubes are fabricated by using pre‐prepared MnO₂ nanowires as the reactive templates. MnO₂ nanowires induce the 1D polymerization of pyrrole monomers and the simultaneous dissolution of the templates affords the hollow tube‐like structure. The loading content of metal nanoparticles in the nanocomposites could be adjusted by simply changing the amount of metal precursors. This work provides an efficient approach to fabricate an important kind of metal/conducting polymer hybrid nanotubes that are potentially useful for electrocatalyst and sensor materials.     

Magnetron sputtering of silver nanowires using anodic aluminum oxide template: a new active substrate of surface enhanced Raman scattering and an investigation of its enhanced mechanism

A high quality anodic aluminum oxide (AAO) template with ordered apertures about 50-80 nm was fabricated by anodizing aluminum in electrolytes through a two-step method, and silver nanowires with diameters from 40nm to 70nm were prepared on this AAO template by magnetron sputtering. On the glass covered with silver nanowires, high quality surface enhanced Raman scattering (SERS) spectra of sudan II (C₁₈H₁₆N₂O) with enhancement factors of 10⁵ were obtained. And comparison of SERS spectra on silver nanowires with the SERS spectra of silver colloids indicates that main enhanced mode is lightning rod effect of nanorods on the Sudan II/silver nanowires system.     

Synthesis, manipulation and conductivity of supramolecular polymer nanowires

The synthesis of supramolecular conducting nanowires can be achieved by using DNA and pyrrole. Oxidation of pyrrole in DNA-containing solutions yields a material that contains both the cationic polypyrrole (PPy) and the anionic DNA polymers. Intimate interaction of the two polymer chains in the self-assembled nanowires is indicated by FTIR spectroscopy. AFM imaging shows individual nanowires to be continuous, approximately 5 nm high and conformationally flexible. This feature allows them to be aligned by molecular combing in a similar manner to bare DNA and provides a convenient method for fabricating a simple electrical device by stretching DNA/PPy strands across an electrode gap. Current-voltage measurements confirm that the nanowires are conducting, with values typical for a polypyrrole-based material. In contrast to polymerisation of pyrrole on a DNA template in bulk solution, attempts to form similar wires by polymerisation at surface-immobilised DNA do not give a continuous coverage; instead, a beads-on-a-string appearance is observed suggesting that immobilisation inhibits the assembly process.     

线状和树枝状银纳米结构、形成机理及表面增强拉曼散射性质(英文)

以聚丙烯酰胺(PAM)为模板,在液相中通过不同浓度的抗坏血酸还原硝酸银能够得到缠结的线状和树枝状银纳米结构.该方法合成条件温和(常温常压)、产率高、成本低、操作简单,并且得到了特殊形貌的缠结收光在谱一对起线的状线和状树银枝纳状米银结纳构.米通结过构透的射形电貌子和显性微质镜进(T行E了M)表,扫征描.研电究子表显明微,镜PA(SMEM对)线、拉形曼产光物谱的和形紫成外起?可了见决吸定性作用.在反应初期,大量新生成的银核被PAM链吸附,小颗粒逐渐长大,进而相连,导致生成了缠结的线状银纳米结构.另外,抗坏血酸的浓度越高,越不利于线状结构的生成.利用对巯基苯胺(PATP)为探针分子研究了银纳米结构的表面增强拉曼散射(SERS)活性,结果表明线状银纳米结构具有较强的表面增强拉曼散射效果.     

Single-walled carbon nanotube-based coaxial nanowires: synthesis, characterization, and electrical properties

We report herein the template-directed synthesis, characterization, and electric properties of single-walled carbon nanotube- (SWNT-) based coaxial nanowires, that is, core (SWNT)-shell (conducting polypyrrole and polyaniline) nanowires. The SWNTs were first dispersed in aqueous solutions containing cationic surfactant cetyltrimethylammonium bromide (CTAB) or nonionic surfactant poly(ethylene glycol) mono-p-nonyl phenyl ether (O pi-10). Each individual nanotube (or small bundle) was then encased in its own micellelike envelope with hydrophobic surfactant groups orientated toward the nanotube and hydrophilic groups orientated toward the solution. And thus a hydrophobic region within the micelle/SWNT (called a micelle/SWNT hybrid template) was formed. Insertion and growth of pyrrole or aniline monomers in this hybrid template, upon removal of the surfactant, produce coaxial structures with a SWNT center and conducting polypyrrole or polyaniline coating. Raman and Fourier transform infrared (FTIR) spectroscopy and scanning (SEM) and transmission (TEM) electron microscopy were used to characterize the composition and the structures of these coaxial nanowires. The results revealed that the micellar molecules used could affect the surface morphologies of the resulting coaxial nanowires but not the molecular structures of the corresponding conducting polymers. Electric properties testing indicated that the SWNTs played the key roles in the conducting polymer/SWNT composites during electron transfer in the temperature range 77 K to room temperature. Compared with the SWNT network embedded in the conducting polymers, the composites within which SWNTs were coated perfectly by the identical conducting polymers exhibited higher barrier heights during electron transfer.     

The excellent performance of nitrogen-doped porous carbon nanowires modified activated carbon as air cathode catalyst for microbial fuel cells

Journal of Solid State Electrochemistry - Nitrogen-doped porous carbon nanowires with polypyrrole as precursor are synthesized by modified oxidation template assembly method. The nitrogen-doped...     

Preparation and characterization of copper/silver bimetallic nanowires with core‐shell structure

Core‐shell copper/silver bimetallic nanowires were prepared by replacement reaction with citric acid and polyvinylpyrollidone at room temperature. A uniform silver coating was obtained by strictly controlling the molar ratio of Ag/Cu. The copper/silver composite was characterized by X‐ray diffraction, scanning electron microscopy, electron probe microanalysis and X‐ray photoelectron spectroscopy. Microscopic analysis shows that a well‐copper/silver core‐shell structure was formed. Thermo‐gravimetry and differential thermal analysis to the composite nanowires show that the silver coatings efficiently inhibit the oxidation of Cu. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and characterization of polypyrrole/graphite oxide composite by in situ emulsion polymerization

This work demonstrates a feasible route to synthesize the layered polypyrrole/graphite oxide (PPy/GO) composite by in situ emulsion polymerization in the presence of cationic surfactant cetyltrimethylammonium bromide (CTAB) as emulsifier. AFM and XRD results reveal that the GO can be delaminated into nanosheets and well dispersed in aqueous solution in the presence of CTAB. The PPy nanowires are formed due to the presence of the lamellar mesostructured (CTA)₂S₂O₈ as a template. The results of the PPy/GO composite indicate the PPy insert successfully into GO interlayers, and the nanofiber‐like PPy are deposited onto the GO surface. Owing to π–π electron stacking effect between the pyrrole ring of PPy and the unoxided domain of GO sheets, the electrical conductivity of PPy/GO composite (5 S/cm) significantly improves in comparison with pure PPy nanowires (0.94 S/cm) and pristine GO (1 × 10^?6 S/cm). © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1329–1335, 2010     

Ag核Au壳双金属复合纳米线的制备及其表面增强拉曼光谱研究

采用氧化铝模板结合交流电沉积技术制备纯银纳米线, 然后通过化学还原方法, 并控制加入的金盐的量, 在已制备好的银线表面包裹不同厚度的金壳层, 得到具有核壳结构的Ag_核Au_壳复合纳米线. 采用电子显微镜(SEM, TEM)和表面增强拉曼光谱对该复合结构纳米线进行相关表征, 纳米线的表面形貌与加入的金盐的量有关. 以苯硫酚(TP)和对巯基苯胺(PATP)为探针分子, 研究了此类复合纳米线的表面增强拉曼散射效应. 并以PATP在金银纳米线表面吸附的表面增强拉曼光谱的差别为探针, 表征了复合纳米线表面金的包裹程度, 结果表明一定厚度的包裹程度可制备无针孔效应的核壳结构金银复合纳米线.     

核-壳结构P(AM-co-MAA)-W-Ag复合微球的制备

以丙烯酰胺(acrylamide, AM)和甲基丙烯酸(methacrylic acid, MAA)的共聚微凝胶(P(AM-co-MAA))为模板, 通过离心沉积法将钨粉沉积于高分子微凝胶表面, 得到具有核-壳结构的P(AM-co-MAA)-W复合微球; 再以经聚乙烯基吡咯烷酮(PVP)修饰的P(AM-co-MAA)-W复合微球为模板, 在硝酸银溶液中充分溶胀后, 通过向反相悬浮体系中缓慢通入氨气, 制备得到了具有核-壳结构的P(AM-co-MAA)-W-Ag双金属复合微球材料. 实验发现, 通过改变制备过程中AgNO3的初始浓度和PVP的用量等条件, 可以改变复合微球表面银的沉积量; 并结合实验结果初步提出了银的形成机理, 即PVP的存在, 不仅可以作为稳定剂固定Ag+离子, 同时可以作为还原剂促进Ag+还原为Ag的反应.     

Preparation of raspberry-like polypyrrole composites with applications in catalysis

Raspberry-like composites were prepared by coating the silver/polypyrrole core/shell composites onto the surface of silica spheres via oxidation polymerization of pyrrole monomer with [Ag(NH₃)₂]⁺ ions as oxidants. The whole process allowed the absence of stabilizers, which greatly improved the quality of the conducting polymer composites. The morphology of the resulting composites was investigated, which can be described as raspberry-like; also, the structure and composition of the composites were characterized in detail. A possible formation mechanism was proposed. The present synthetic strategy substantially extended the scope of metal/conducting polymer composite synthesis. The raspberry-like composites exhibited excellent catalytic properties in the reduction of methylene blue dye with the reducing agent of sodium borohydride.     

Direct synthesis of silver/polymer/carbon nanocables via a simple hydrothermal route

High-yield silver/polymer/carbon nanocables were synthesized via a one-step simple hydrothermal route by using silver chloride and glucose as precursors. High-resolution TEM and element mapping proved that as-prepared nanocables consist of a silver nanowire core, a polymer inner shell, and a graphitic carbon outer shell. A three-step growth mechanism was proposed to explain the growth of such three-layer nanocables, i.e. the formation of silver nanowires, the glycosidation of glucose molecules on silver nanowire surface and the carbonization of the outmost glycosidation layer. We believe that reaction temperature plays the key role in the polymerization of glucose and sequent surface-carbonization.     

负载纳米银复合微球制备及其催化性能

以具有温度和pH双重敏感性能的N-异丙基丙烯酰胺(NIPAM)共聚丙烯酸(AA) P(NIPAM-co-AA)高分子微凝胶为模板, 以乙醇为还原剂, 原位还原得到负载纳米银的微米尺度Ag/P(NIPAM-co-AA)复合微凝胶材料. 通过扫描电子显微镜(SEM)、X射线衍射(XRD)仪和紫外-可见(UV-Vis)分光光度计等对复合材料的形貌、组成和催化性能进行表征. 研究结果表明, Ag/P(NIPAM-co-AA)复合微球具有均一的表面结构, 微凝胶的限域作用显著提高了纳米银的分散性和稳定性. 另外, Ag/P(NIPAM-co-AA)复合微球对对硝基苯酚(4-NP)的还原具有较好的催化活性, 且其催化活性与微凝胶网络结构的溶胀、收缩行为有一定关系, 即模板微凝胶的温敏特性可以实现对对硝基苯酚催化反应活性的调控作用.     

Controlled electrochemical synthesis of conductive polymer nanotube structures

We have investigated the electrochemical synthetic mechanism of conductive polymer nanotubes in a porous alumina template using poly(3,4-ethylenedioxythiophene) (PEDOT) as a model compound. As a function of monomer concentration and potential, electropolymerization leads either to solid nanowires or to hollow nanotubes, and it is the purpose of these investigations to uncover the detailed mechanism underlying this morphological transition between nanowire and nanotube. Transmission electron microscopy was used to characterize electrochemically synthesized PEDOT nanostructures and measure the extent of their nanotubular portion quantitatively. The study on potential dependency of nanotubular portion shows that nanotubes are grown at a low oxidation potential (1.2 V vs Ag/AgCl) regardless of monomer concentration. This phenomenon is attributed to the predominance of electrochemically active sites on the annular-shape electrode at the pore bottom of a template. The explanation was supported by a further electrochemical study on a flat-top electrode. We elaborate the mechanism by taking into account the effect of electrolyte concentration, temperature, and template pore diameter on PEDOT nanostructures. This mechanism is further employed to control the nanotube dimensions of other conductive polymers such as polypyrrole and poly(3-hexylthiophene).     

Fabricating and aligning pi-conjugated polymer-functionalized DNA nanowires: atomic force microscopic and scanning near-field optical microscopic studies

We report a simple method to functionalize DNA with pi-conjugated polymer, forming highly aligned and integrated arrays of pi-conjugated polymer nanowires of a few nanometers diameter. pi-conjugated polymer, polyphenazasiline, having alkylammonium salts on the N atom (PPhenaz-TMA), synthesized in this study can be directly attached to DNA, which can be organized along stretched and aligned DNA molecules on surfaces as a template. Furthermore, PPhenaz-TMA/DNA nanowires were stretched and aligned on surfaces, even when PPhenaz-TMA/DNA complexes formed in solutions. The resulting PPhenaz-TMA/DNA nanowires could be easily converted to oxidized states or metallic nanowires by using adequate oxidant or metal salts. The direct visualization of PPhenaz-TMA/DNA nanowires and its structural changes have been studied by atomic force microscopy and scanning near-field optical microscopy.     

Formation of nanowire striations driven by Marangoni instability in spin-cast polymer thin films

Parallel striations made of silver nanowires were formed through the Marangoni instability induced during spin casting of poly(2-vinyl pyridine)/silver nanowire/chloroform solutions. The striation patterns of the silver nanowires resembled those obtained from spin casting of the corresponding neat polymer solutions, indicating essentially the same driving mechanism (i.e., the Marangoni instability). The silver nanowires were found to concentrate in the valleys of the striation pattern to balance the nonuniform surface tension distribution in the polymer thin film. The resulting nanowire striation patterns were found to depend on polymer concentration, rotational speed, and nanowire loading. Interestingly, this nanowire striation phenomenon was found to be independent of the substrate characteristics, hydrophobic or hydrophilic.     

利用模板法制备Ag纳米线

利用阳极氧化铝（AAO）作为模板,制备出高定向的Ag纳米线．Ag纳米线的形貌由环境扫描电镜证实,并通过X-射线能谱（EDX）、X-射线粉末衍射谱（XRD）测试手段进行了表征．     

Characterization of polypyrrole-silver nanocomposites prepared in the presence of different dopants

Conducting polypyrrole (PPy) powder synthesized by using FeCl3 x 6 H2O and/or Fe(NO3)3 oxidants was impregnated in silver salt solutions. The stability and decomposition of the material was followed by thermogravimetric measurements. The total silver content was determined by atom absorption spectroscopy (ICP-AAS). The heat and electric conductivities of the composites were measured and correlated with the silver content. The incorporated silver was speciated and measured by X-ray diffraction (XRD). The spectra proved that the chemical state of the silver incorporated into the composite depends on the anion used in the polymerization process. In the case of the polymerization in a nitrate ion containing solution, the impregnation leads exclusively to the formation of metallic silver. The size distribution of the AgCl and Ag nanoparticles, determined from transmission electron microscopy (TEM) pictures in the different composites, proves the formation of a rather uniform species below 10 and 7 nm, respectively. The observations can be correlated with the different interactions in the PPy-chloride/nitrate-silver systems. The redox type interaction based conclusions can be considered as a guide during the preparation of other metal-conducting polymer composites.