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1.
The cation-exchange property of oxidatively treated carbon nanotubes (CNTs) is newly reported. Single-wall carbon nanotubes (SWNTs), which were oxidatively treated, were immobilized on a glassy carbon surface and, on this CNT-modified electrode, Cu(II) ions were spontaneously adsorbed and their redox waves electrochemically measured. It is suggested that the adsorption of the cationic Cu(II) ions occurs by their electrostatic interaction with the negatively charged carboxylic anions on the CNTs after the ion-exchange with protons. The surface coverage of the adsorbed Cu(II) ions depending on the dipping time, the amount of immobilized CNTs, and the Cu(II) concentration was estimated from the electrochemical chronocoulometric measurements. The effect of the ionic strength on the adsorption of the Cu(II) ions was investigated and the adsorption strengths of various alkali metal cations and protons were compared. It is hoped that this new cation-exchange property of CNT-modified electrodes may extend their range of electrochemical applications.  相似文献   

2.
    
A multiple stimuli-responsive actuator with an ability of rapid and sensitive responding is highly desirable for the development of biomimetic actuation applications. Herein, a bilayer actuator with fast and sensitive responses to acetone vapor and light stimuli is reported based on polyvinylidene fluoride (PVDF) membrane with a hierarchical porosity and macroscopic carbon nanotubes (CNTs) assembled film. The CNTs film with uniform and tunable thickness is prepared by a macroscopic interfacial assembly strategy and transferred integrally onto the PVDF membrane. Under the infrared light, this CNTs/PVDF bilayer actuator can bend rapidly within 1 s and generate large stress. Moreover, for the acetone vapor stimuli, the actuator bends within 0.19 s and also reverses in 1.24 s to the initial state, showing sensitive and fast responses to acetone stimuli, as well as outstanding stability and repeatability.  相似文献   

3.
    
We report a study of the electrical and mechanical effects of the inclusion of a thin layer of multiwalled carbon nanotubes (MWCNTs) into the surface of polydimethylsiloxane (PDMS) as a method of creating an electrically actuated, flexible microfluidic valve. Samples of PDMS with various surface loadings of MWCNTs were prepared and tested using a uniaxial tension tester, combined with a four‐point probe electrical test. In contrast to other works reporting the inclusion of MWCNTs in the bulk of the material, we have found that inclusion of the MWCNTs on the surface only has no discernible effect on the mechanical properties of the PDMS samples, but causes a significant and repeatable change in the electrical performance. We have found that a loading of 4.16 g m?2 results in an electrical resistivity of 7.31 × 10?4 Ω cm, which is 200% lower than that previously reported for bulk inclusion samples. The microstructure of the MWCNTs was found to consist of both individual fibers and spherical clumps of fibers. We suggest that, due to the microstructure of the MWCNTs used in this study, the mechanical properties can be modeled as a thin layer of particulates, while the electrical properties can be modeled as a thin bed of bulk MWCNTs. © 2012 Society of Chemical Industry  相似文献   

4.
本文综述了单壁碳纳米管的制备方法,重点阐述了化学气相沉积法的合成运用,并对目前碳纳米管在聚合物基纳米复合材料方面的研究做了综合阐述。  相似文献   

5.
The cyclic voltammetric behaviors of empty nanotubes and toluene-filled nanotubes were described. When the nanotube films exposed to air for one night, a pair of redox waves was observed that is probably ascribed to the presence of oxygen-containing groups bound to the surface of the nanotubes. Toluene-filled nanotube film is demonstrated to catalyze the electrochemical response of biomolecules such as dopamine and epinephrine, while empty multi-wall carbon nanotube film shows no or less electrocatalytic behavior to these biomolecules. This suggests that filled nanotubes have some particular properties compared to empty multi-wall carbon nanotubes and the development of filled nanotubes is necessary.  相似文献   

6.
Nitrogen-doped carbon (CNx) nanotubes were synthesized with carbon nanotubes (CNTs) as catalyst by detonation-assisted chemical vapor deposition. CNx nanotubes exhibited compartmentalized bamboo-like structure. Electron energy loss spectroscopy and elemental mapping studies indicated that the synthesized tubes contained high concentration of nitrogen (ca. 17.3 at.%), inhomogeneously distributed with an enrichment of nitrogen within the compartments. X-ray photoelectron spectroscopy analysis revealed the presence of pyridine-like N and graphitic N incorporated into the graphitic network. The catalytic activity of CNTs for CNx nanotube growth was ascribed to the nanocurvature and opening edges of CNT tips, which adsorbed Cn/CN species and assembled them into CNx nanotubes.  相似文献   

7.
    
The purpose of the current review article is to present a compherensive understanding regarding pros and cons of carbon nanotube–related nanocomposites and to find ways in order to improve the performance of nanocomposites with new designs. Nanomaterials including carbon nanotubes (CNTs) are employed in industrial applications such as supercapacitors, and biosensors, and etc. The present article has been prepared in three main categories. In the first part, carbon nanotube types have been presented, as single-walled carbon nanotubes, multi-walled carbon nanotubes, and also equivalent circuit models, which have been used to more clarify the experimental measurements of impedance. In the second part, nanocomposites with many carbon, inorganic and polymeric materials such as polymer/CNT, activated carbon/CNT, metal oxide/CNT, and carbon fiber/CNT have been investigated in more detail. In the third part, the focus in on the industrial applications of CNTs. including supercapacitors, biosensors, radar absorbing materials, solar cells, and corrosion protection studies. This review article explains the latest advances in carbon nanotubes and their applications in electrochemical, electrical and optical properties of nanocomposites.  相似文献   

8.
综述了碳纳米管的几种制备工艺和相关的生长机制,还介绍了近两年来碳纳米管制备的进展情况,包括新型制备技术、特殊结构的碳纳米管制备。  相似文献   

9.
The effect of metal particles on the photoluminescence (PL) and the Raman spectra of functionalized SWCNTs in aqueous solutions was systematically investigated by studying three different metal particles (gold, cobalt, and nickel) on three different SWCNT suspensions (DNA-, RNA-, and sodium deoxycholate salt (DOC)-functionalized SWCNTs). Substantial enhancement of the PL intensities was observed, while the Raman spectra remained unchanged, after gold, cobalt, or nickel particles were introduced into RNA-SWCNT aqueous suspensions. Almost the same results were obtained after the same metal particles were added to DNA-SWCNT aqueous suspensions. However, both the PL and the Raman spectra did not exhibit any change at all after the same metal particles were introduced into DOC-SWCNT aqueous suspensions. The unusual PL enhancements observed in this work cannot be accounted for by the three well-known mechanisms in the literature: surface-enhanced Raman scattering effect, Förster resonance energy transfer in a rebundling of isolated SWCNTs, and pH changes of the aqueous solutions.  相似文献   

10.
Carbon Nanotubes for Supercapacitor   总被引:2,自引:0,他引:2  
As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs) and their composites. The purpose is to give a comprehensive understanding of the advantages and disadvantages of carbon nanotubes-related supercapacitor materials and to find ways for the improvement in the performance of supercapacitor. We first discussed the effects of physical and chemical properties of pure carbon nanotubes, including size, purity, defect, shape, functionalization, and annealing, on the supercapacitance. The composites, including CNTs/oxide and CNTs/polymer, were further discussed to enhance the supercapacitance and keep the stability of the supercapacitor by optimally engineering the composition, particle size, and coverage.  相似文献   

11.
Hao Kong  Chao Gao  Deyue Yan 《Polymer》2005,46(8):2472-2485
Two kinds of polyelectrolyte: polyacrylic acid (PAA) and poly(sodium 4-styrenesulfonate) (PSS), were grafted onto the convex surfaces of multiwalled carbon nanotubes (MWNTs) by surface-initiating ATRP (atom transfer radical polymerization) from the initiating sites previously anchored onto the convex surfaces of MWNTs. The grafted polyelectrolyte can be efficiently quantified by the feed ratio of monomer to MWNT-based macroinitiator, and the maximum amount of grafted polymer is higher than 55 wt%. The polyelectrolyte-coated MWNTs resembled core-shell structures justified by the TEM images of the samples obtained, which provided direct evidence for the covalent modification of MWNT. FTIR, 1H NMR and TGA were used to determine the chemical structure of the resulting products. Comparison of UV-Vis spectra demonstrated that the products were water-soluble, and that PSS was more effective for improving the water solubility of carbon nanotubes. Using the polyelectrolyte- and carboxylic acid-functionalized MWNTs as templates, and poly(2-(N,N-dimethylaminoethyl) methacrylate (PDMAEMA)/hyperbranched polysulfone amine (HPSA) and PSS as polycation and polyanion, respectively, layer-by-layer (LbL) electrostatic self-assembly was conducted in order to explore the application of the functionalized nanotubes. It was found that the functionalized MWNTs have a high efficiency for loading polyelectrolytes by the LbL approach (the adsorbed polymer quantity is higher than 10 wt% in one assembling step). TEM observations showed that the assembled polymer shell on the MWNT surfaces was very even and flat.  相似文献   

12.
纳米碳管提纯的研究进展   总被引:2,自引:1,他引:2  
对当前给米碳管的各种提纯方法进行了分类、总结。同时对各类提纯方法的机理进行了讨论,简述了本研究小组在提纯方面的工作。  相似文献   

13.
The present study aimed at development of a method for synthesizing multi-walled carbon nanotubes (CNTs) on carbon paper substrates (CP) at densities as high as those so far reported for CNTs formed on quartz substrates. Applying conditions optimized for CNTs synthesis on quartz substrates, in which CP was heated at 1073 K, being placed parallel to the flow of m-xylene/ferrocene vapor, resulted in formation of extremely few deposits on CP. Forced vapor flow through the CP greatly improved the frequency and homogeneity of deposition of the Fe-bearing nanoparticles, but these became encapsulated by carbon and deactivated. The addition of H2S to the vapor further enhanced nanoparticle deposition. Moreover, it enabled the subsequent formation of CNTs at densities as high as 2-6 × 109 cm−2. In order to realize such high population densities, it was found essential to perform CVD in a two-stage sequence commencing with nanoparticles deposition at 1073 K followed by the formation and growth of CNTs at 1273 K, with the H2S concentration in the vapor phase optimized throughout within a range of 0.014-0.034 vol%.  相似文献   

14.
摘要:以不同长径比和比表面积的五种碳纳米管(CNT)与聚碳酸酯(PC)复合,制备导电塑料,观察CNT在PC中的分散情况。发现CNT的长径比越大,导电塑料的体积电阻率越小,加工难度越大,单壁碳纳米管(SWCNT)长径比过大,在PC中更容易缠绕团聚,导电塑料的体积电阻率反而上升;在PC中添加不同质量分数的多壁碳纳米管阵列(A-MWCNT),发现A-MWCNT质量分数为1%时,导电塑料的体积电阻率为16.0 Ω·cm,导电性能远超导电炭黑,其添加量越多,体积电阻率越小,但导电塑料越难加工,当添加质量分数为15%时,体积电阻率下降已不明显;将A-MWCNT与PC复合制备A-MWCNT导电塑料母粒,利用导电塑料母粒与PC复合制备A-MWCNT质量分数为1%的PC导电塑料,与直接混合制备的A-MWCNT质量分数为1%的导电塑料相比,其体积电阻率下降48.5%,平衡扭矩下降25%,力学性能损失较少。  相似文献   

15.
    
《Ceramics International》2019,45(11):13988-13998
Introducing carbon nanotubes (CNTs) by electrophoretic deposition (EPD) is a promising method to improve the strength and toughness of carbon/carbon (C/C) composites. Herein, a new reinforcing mechanism called “compressive residual thermal stress (RTS) induced crack deflection” has been reported. Concretely, CNTs, with different loading content, were introduced by EPD method. Results showed that the CNT content had little influence on CNT-induced matrix refinement. However, the strength of the CNT-doped C/C composites increased with the rising content of CNTs and cracks could only deflect when the CNT interface reached a certain thickness. A theory based on compressive RTS induced crack deflection was built to interpret this discrepancy. Tensile stress existed at the interface in pure C/C composites, while compressive stress occurred and increased with the rising thickness of the CNT interface, which were verified by finite element analysis and Raman test. Calculation revealed that compressive stress exceeded 30 MPa at the crack tip could make the crack deflection happen more easily since it released more strain energy than penetration.  相似文献   

16.
Ning Yu 《Polymer》2011,52(2):472-480
As a typical engineering plastic and high-crystallization polymer, polyoxymethylene (POM) has been successfully wrapped on single-walled carbon nanotubes (SWCNTs) using a simple supercritical carbon dioxide (SC CO2) antisolvent-induced polymer epitaxy method. The characterization results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that the SWCNTs are coated by laminar POM with the thicknesses of a few nanometers. The polymer adsorption on CNTs via multiple weak molecular interactions of CH groups with CNTs has been identified with FTIR and Raman spectroscopy. The experimental results indicate that the decorating degree of POM on the surface of CNTs increases significantly with the increase of SC CO2 pressure, and accordingly the dispersion of SWCNT modified by POM at higher pressure are more excellent than that of obtained at lower pressure. Further the processing stability of POM/CNTs composites are investigated by differential scanning calorimetry and thermogravimetric analysis. The experimental results obtained show that their thermal stability behavior is closely related to surface properties of CNTs. Apparently, the composites with POM-decorating SWCNTs as the filler shows higher melting points compared to the POM composites with pristine SWCNTs as the filler. Therefore, we anticipate this work may lead to a controllable method making use of peculiar properties of SC CO2 to help to fabricate the functional CNTs-based nanocomposites containing highly crystalline thermoplastic materials such as POM.  相似文献   

17.
Fabrication of superhydrophobic surfaces has been widely investigated due to their wide range of applications. Here, synthesis of self-assembled aligned carbon nanotubes (ACNT)/amorphous carbon (a-C) nanosphere hybrid film is reported. Carbon plasma produced by FCVA was used to deposit a-C nanospheres on the ACNT films fabricated by PECVD. The superhydrophobic properties of the surface was investigated by static contact angle (CA) measurement. It is found that the surface morphology of the film which depends on the size of the a-C nanospheres, has a great influence on the hydrophobic properties of the surface. The hydrodynamic properties of the surface is discussed in terms of both Cassie and Wenzel mechanisms. The microstructure of the films is also investigated by XPS and HRTEM. It is shown that the bombardment of the CNTs with high energy carbon ions will damage the crystalline structure of the CNT walls as well.  相似文献   

18.
T.E. Chang  A. Kisliuk  R. Pyrz 《Polymer》2005,46(2):439-444
We analyzed mechanical properties and structure of polypropylene fibers with different concentrations of single-wall carbon nanotubes (SWNTs) and draw down ratios (DDR). Tensile tests show a three times increase in the Young's modulus with addition of only 1 wt% SWNT, and much diminished increase of modulus with further increase in SWNT concentration. Microscopic study of the mechanism of reinforcement by SWNT included Raman spectroscopy and wide-angle X-ray diffraction (WAXD). The results show linear transfer of the applied stress from the polymer matrix to SWNT. Analysis of WAXD data demonstrates formation of a β-crystal phase in polypropylene matrix under the strain.  相似文献   

19.
本文介绍了国内外碳纳米管(CNTS)最新研究进展,分析了制备碳纳米管所必需的3个关键条件:碳源、催化剂、能源;并分别研究了它们对碳纳米管生长的影响。通过碳纳米管的生长机理探讨了大规模制备碳纳米管的可行性。  相似文献   

20.
T.-E. Chang 《Polymer》2006,47(22):7740-7746
The morphologies, electrical and mechanical properties and structure of polystyrene (PS) composites with varying concentrations of single-wall carbon nanotubes (SWNT) are analyzed. Using Raman spectroscopy and electron microscopy, we demonstrate that initial thermal annealing of SWNT significantly improves their dispersion in PS. In dielectric measurements, the annealed SWNT/PS composites show higher electrical conductivity and a lower percolation threshold (less than 0.3 wt%) than the raw SWNT/PS composites, which provides further evidence of good dispersion of the annealed SWNT in PS. Raman spectra of composites under tension show good transfer of an applied stress from the polymer matrix to SWNT. However, mechanical moduli of the annealed SWNT/PS composites are only increased slightly. The reason for this discrepancy remains unclear.  相似文献   

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