Multi-wall carbon nanotubes with nitrogen-containing carbon coating

Polyaniline coating was deposited on the surface of multi-wall carbon nanotubes of Russian and Taiwanese origin in situ during the polymerization of aniline. The deposited polyaniline film was subsequently carbonized under an inert atmosphere at various temperatures to produce coaxial coating of the carbon nanotubes with nitrogen-containing carbon. The new materials were investigated by infrared and Raman spectroscopies, which demonstrated the conversion of the polyaniline coating to a carbonized structure. X-ray photoelectron spectroscopy proved that the carbonized overlayer contains nitrogen atoms in various covalent bonding states. Transmission electron microscopy confirmed the coaxial structure of the composites. The Brunauer-Emmett-Teller method was used to estimate the specific surface area, the highest being 272 m² g^?1. The conductivity of 0.9–16 S cm^?1 was measured by the four-point method, and it was only a little affected by the carbonization of the polyaniline coating.     

磺化碳纳米管改性聚苯胺复合材料的合成与超级电容特性

运用重氮化技术制备了水溶性磺化碳纳米管,在此基础上,以不同直径的磺化碳纳米管(1～2 nm,<8 nm,10～20 nm,30～50 nm)为载体,采用原位氧化聚合方法合成了一系列磺化碳纳米管改性聚苯胺复合材料.红外和紫外-可见光谱分析表明,聚苯胺与磺化碳纳米管之间存在π-π相互作用,并形成了电荷转移复合物;且随着碳纳...     

Synthesis and electrochemical properties of composites based on carbon nanotubes and polyaniline

composites made of polyaniline and multiwalled carbon nanotubes have been electrochemically synthesized. The modification of multiwalled carbon nanotubes by a salt of phenyldiazonium significantly increases the redox currents of the polyaniline matrix in the composite. As a result of modification, the conformational state of polyaniline macrochains changes, leading to changes in the morphology, structure, and chemical composition of the composite.     

Green synthesis of polymer nanofibers and their composites as flame‐retardant materials for polymer nanocomposites

Polyaniline nanofibers and their composites with carbon nanotubes were developed as an effective flame‐retardant material using a facile green method. Polyaniline nanofibers were used as a smart flame‐retardant for acrylonitrile–butadiene–styrene polymer. The polyaniline nanofibers were dispersed in polymer matrix forming well‐dispersed polymer nanocomposites. Effect of polyaniline nanofiber mass ratio on the polymer nanocomposite properties was studied. Polyaniline nanofiber composites with carbon nanotubes were also dispersed in polymer matrix. The thermal stability and flammability properties of the polymer nanocomposites were investigated. The rate of burning of polymer nanocomposites achieved 82.5% reduction (7.32 mm/min) compared with virgin polymer (42.5 mm/min). The reduction in peak heat release rate and total heat release of the polymer nanocomposites containing nanofibers achieved 74 and 34%, respectively. Interestingly, the average mass loss rate was significantly reduced by 58% and the emission of carbon monoxide and carbon dioxide gases were suppressed by 20 and 47%, respectively. The effect of polyaniline nanofibers composites on the flammability of polymer nanocomposites was also studied. Polyaniline nanofibers and their composites were characterized using Fourier transform infrared spectroscopy and transmission and scanning electron microscopy. The dispersion of polyaniline nanofibers in polymer nanocomposites was characterized using transmission electron microscopy. The different polymer nanocomposites were characterized using thermogravimetric analysis, UL94 flame chamber, and cone calorimeter tests. Copyright © 2016 John Wiley & Sons, Ltd.     

Nanocomposites with mixed electronic and protonic conduction for electrocatalysis

Novel multipurpose electrode materials that have various catalytic applications are developed. The materials are composites based on multiwalled carbon nanotubes and electroconducting polymer polyaniline, organized as “fiber in a jacket.” Nanoparticles of metallic platinum and compounds of transition metals are additionally immobilized in the polymer layer. It is demonstrated experimentally that the materials possess high electronic and protonic conductance, thermal stability, hydrophilicity, large specific surface area, and considerable porosity.     

Polyanine and its composites as sorbents of influenza viruses

Polyaniline and its composites with carbon nanotubes or silver nanoparticles are prepared and characterized via electron microscopy, spectroscopy, conductometry, and BET analysis. The in vitro and in vivo toxicities of the materials are studied, and then the materials are used as sorbents of the influenza A and B viruses. It is shown that the best sorption capacity with respect to all of the virus strains is exhibited by the polyaniline composite with silver, which provides for almost complete removal of viruses from aqueous solutions.     

Facile synthesis of water-soluble multi-wall carbon nanotubes and polyaniline composites and their application in detection of small metabolites by matrix assisted laser desorption/ionization mass spectrometry

Multi-wall carbon nanotubes and polyaniline composites were synthesized via a simple hydrothermal reaction, and the as-made composites were successfully applied in the analysis of small molecular-weight metabolites as a novel matrix by matrix assisted laser desorption/ionization mass spectrometry.     

高分子量聚苯胺/碳纳米管复合材料的合成与表征

在导电聚合物中,聚苯胺（PANI）因其导电性能优良,环境稳定性好,合成工艺简单,原料成本低廉等优点,被认为是最有可能实际应用的导电聚合物．然而用传统方法合成的聚苯胺由于其分子量小,分子链中存在缺陷而使其导电性能和力学性能大大降低,从而限制了其实际应用．而高分子量聚苯胺的导电性能和力学性能比一般聚苯胺有较大的提高．     

Construction of a carbon nanotube/diamond hybrid functionalized electrode surface

Multiwalled carbon nanotubes were attached to the surface of boron-doped diamond by electropolymerization using a bridge of polyaniline. A carbon nanotube/diamond hybrid functionalized surface was obtained and testified by field emission scanning electron microscopy. The electrochemical impedance spectroscopy and cyclic voltammetry measurements revealed that this carbon hybrid surface possessed low electron-transfer resistance, large double-capacitance value, and high electrocatalytic ability. This indicated that this functionalized surface had a variety of potential sustainable technology applications such as in supercapacitors, biomolecule-sensing devices.     

In situ fabrication of a water-soluble, self-doped polyaniline nanocomposite: the unique role of DNA functionalized single-walled carbon nanotubes

Dispersion of carbon nanotubes into solvents affects their surface chemistries, electronic structures, and subsequent functionalization. In this Communication, a water-soluble self-doped polyaniline nanocomposite was fabricated by in situ polymerization of the 3-aminophenylboronic acid monomers in the presence of single-stranded DNA dispersed- and functionalized-single-walled carbon nanotubes. For the first time, we found that the carbon nanotubes became novel active stabilizers owing to the DNA functionalization. The nanotubes reduced the polyaniline backbone from the unstable, degradable, fully oxidized pernigraniline state to the stable, conducting emeraldine state because of their reductive ability, which could improve the chemical stability of the self-doped polyaniline. Electrical measurements demonstrate that the conductivity of the nanocomposite was much higher than that of the pure self-doped polyaniline in both acidic and neutral solutions.     

聚苯胺/分级碳纳米管复合材料的制备与性能研究

在众多的导电高分子中，聚苯胺具有原料易得、合成简便、能进行快速与可逆的氧化还原反应、可储存高密度的电荷等优点，在能源、光电子器件、电容器、传感器、分子导线和分子器件，以及电磁屏蔽、金属防腐和隐身技术等领域有着诱人的应用前景．近年来，将导电聚苯胺用于超电容器，倍受人们的广泛关注．     

氢键型碳纳米管增强自修复复合材料的制备和表征

使用低聚酸、二乙烯三胺以及尿素为原料,碳纳米管为增强剂,制备出兼具良好力学性能和室温(30 ℃)自修复性能的氢键型自修复复合材料,同时对材料通过氢键进行自修复的机制进行了合理推测。 首先,对不同碳纳米管添加量的自修复材料进行应力-应变性能测试。 结果发现,随着碳纳米管的添加,材料的应力、应变均有所提高,添加质量分数9%碳纳米管时,材料的应力达到4.1 MPa、应变达到6%以上。 对添加质量分数9%碳纳米管的自修复材料进行表面形态、自修复性能以及热稳定性能测试。 结果表明,碳纳米管与材料有良好的相容性,材料的表面与切面形态相似;在室温下自修复24 h,自修复效率达到100%;10次断裂-修复循环中自修复效率仍能保持90%以上;材料具有良好的热稳定性,最大失重速率下的温度为474.3 ℃。 为下一代类皮肤传感器以及可穿戴智能设备提供了一种选择,为未来该类型自修复聚合物复合材料在高拉伸强度领域的应用奠定了技术基础。     

The carbon nanotubes-polyaniline composites and their effect on catalytic properties of deposited catalysts

Composites of functionalized single-wall carbon nanotubes and polyaniline are deposited onto electrodes by in situ electrochemical polymerization. Their electrochemical behavior and differential capacitance are studied by cyclic voltammetry, electrochemical impedance spectroscopy, and chronovoltamperometry. The differential capacitance of the composite electrode exceeds that of pure polyaniline film deposited onto electrode, which can be explained by the nanotubes’ loosening effect on the polyaniline structure. The composite-electrode capacitance is as large as 1000 F g⁻¹ or higher. Thus obtained composite films were used as a support for deposited platinum-ruthenium catalyst. The Pt-Ru structure and catalytic properties in the methanol oxidation reaction are studied. It is shown that the specific current of methanol oxidation at Pt-Ru is larger by a factor of 7–15 than those measured when pure polyaniline, pure carbon nanotubes, or standard Vulcan XC-72 carbon black are used as supports. It is found that the catalytic activity is the same for all studied supports, provided the current is reduced to the unit of Pt-Ru true surface area. Thus, the observed large catalytic effect is associated with the structure and high dispersivity of the electrodeposited metals incorporated to the single-wall carbon nanotubes-polyaniline composite.     

Ternary composites of multi-wall carbon nanotubes,polyaniline, and noble-metal nanoparticles for potential applications in electrocatalysis

Multi-wall carbon nanotubes were coated with a conducting polymer, polyaniline phosphotungstate. Such composite structures have mixed electronic and proton conductivity, high surface area and porosity. These materials were decorated with catalytically-active noble metals — Pt, Pd, and Rh. Metal nanoparticles were uniformly distributed in the polymer matrix. Such ternary composites can be considered as electrode materials in sensors, electrolysers, supercapacitors, and especially in low-temperature fuel cells with a proton-conducting polymer membrane.     

有序介孔二氧化硅-碳纳米管复合材料载Pt 及其电催化性能

以十六烷基三甲基溴化铵(CTAB)为结构导向剂, 正硅酸乙酯(TEOS)为硅源, 通过添加碳纳米管(CNTs), 制备介孔二氧化硅包覆碳纳米管网状结构的复合材料(C/Si). X 射线衍射(XRD)和透射电子显微镜(TEM)显示, 介孔二氧化硅的孔道结构高度有序, CNTs 均匀分散于二氧化硅刚性骨架中. 以其为载体微波负载制备了Pt-C/Si-x 纳米粒子催化剂,研究了催化剂在硫酸和甲醇溶液中电催化性能, 结果表明, 具有较高导电性能的复合材料保持了二氧化硅的均匀的孔道结构有利于电解液存储和质子传输, 使得该催化剂显示了良好的电催化活性. 其中碳纳米管添加含量为40 mg 时,催化剂在H₂SO₄ 电解液中的电化学活性面积高达120.9 m²·g^-1, 远大于Pt/CNTs 的电化学活性面积, 对甲醇的催化峰电流也达80.3 mA·cm^-2. 预示其作为直接甲醇燃料电池催化剂载体具有良好的应用前景.     

Linear and nonlinear optical characterization of a tetraphenylporphyrin-carbon nanotube composite system

We present a study of tetraphenylporphyrin composites formed with single-walled carbon nanotubes (SWNTs). Stable porphyrin/SWNT composite solutions were obtained by non-covalent bonding between the carbon nanotubes and conjugated tetraphenylporphyrin molecules. Transmission electron microscopy reveals porphyrin molecules adhering to the nanotube surface. We report on the first complete linear and nonlinear optical characterization of these nanocomposite materials. The composite solutions were found to be superior optical limiters to nanotubes alone, and to all porphyrin systems studied, including metalloporphyrins.     

Composite materials based on polyaniline and multiwalled carbon nanotubes: Morphology and electrochemical behavior

Composites based on polyaniline are prepared via the chemical oxidative polymerization of aniline in the presence of multiwalled carbon nanotubes modified by the sorption of the co-oxidants IrC ₆ ^2? and 2,2′-azino-bis(3-ethyl-benzthiazolin-6-sulfonate). The approach used here, in combination with corresponding conditions of polymerization, ensures the synthesis of composite materials with a high morphological homogeneity of the polymer phase. The study of the electrochemical properties of composites (the reversibility of redox transitions and the stability of capacity parameters) indicates that that they are strongly influenced by the morphological features of the polymer coating. The composite prepared with the use of nanotubes modified by 2,2′-azino-bis(3-ethyl-benzthiazolin-6-sulfonate) possesses better electrochemical characteristics. This effect is associated with a closer to perfect morphology of the polymer coating, a coaxial polyaniline shell highly uniform in thickness along the entire length of nanotubes.     

The electronic role of DNA-functionalized carbon nanotubes: efficacy for in situ polymerization of conducting polymer nanocomposites

We have found that the polymerization process was 4,500 times faster when a self-doped polyaniline nanocomposite was fabricated using in situ polymerization in the presence of single-stranded DNA-dispersed and -functionalized single-walled carbon nanotubes (ssDNA-SWNTs). More importantly, the quality of the composite was significantly improved: fewer short oligomers were produced, and the self-doped polyaniline backbone had a longer conjugation length and existed in the more stable and conductive emeraldine state. The functionality of the boronic acid group in the composite and the highly improved electronic performance may lead to broad applications of the composite in flexible electronic devices. Blending of preformed polymer with carbon nanotubes is straightforward and widely used to fabricate nanocomposites. We demonstrate that this simple mixing approach might not fully and synergistically combine the merits of each individual component. Surprisingly, these advantages also cannot be obtained using in situ polymerization with preoxidized ssDNA-SWNTs, which is renowned as the "seed" method for production of conducting-polymer nanowires. The electronic structures of the carbon nanotubes and the monomer-nanotube interaction during polymerization greatly impact the kinetics of nanocomposite fabrication and the electronic performance of the resulting composites.     

高性能环氧树脂/碳纳米管复合物的热分析研究

用差示扫描量热仪(DSC)、热失重分析仪(TGA)和动态力学热分析仪(DMTA)研究了多壁碳纳米管(MWNTs)/高性能4,4′-二氨基二苯甲烷四缩水甘油环氧树脂(TGDDM)/4,4′-二氨基二苯基砜(DDS)复合物的热性能.Kissinger和Flynn-Wall-Ozawa的非等温固化动力学研究发现,随着MWNTs含量的增加,复合物固化反应的活化能先减小后增大.TGA研究表明,MWNTs的添加对环氧树脂热稳定性影响很小.碳纳米管填充到TGDDM/DDS体系后,复合物的储存模量随着MWNTs含量的增加而增大,而玻璃化温度却随之减小.     

Synthesis of Multishell Carbon Nanotube Composites via Template Method

Multishell nanotubes of polyaniline and carbon were synthesized via a template approach. A thin layer of MnO₂ coated on carbon nanotubes acts as a reactive template for the consequent formation of the polyaniline coating. The polyaniline-carbon nanotubes show enhanced dispersibility in water and can be possibly used as a functional material of electrochemical capacitors with improved performance. The general method operates by coating carbon nanotubes on functional materials such as poly (3,4-ethylenedioxythiophene), polypyrrole, silica, and carbon.