共查询到20条相似文献,搜索用时 15 毫秒
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Thermal stability of copper coating on carbon fibres 总被引:3,自引:0,他引:3
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J. Jayapriya Judy Gopal V. Ramamurthy U. Kamachi Mudali Baldev Raj 《Composites Part B》2012,43(3):1329-1335
Electron transfer in microbial fuel cell and biosensors could be facilitated through high conductive materials with enhanced active surface area and appropriate redox potential suited to microbial metabolism. In the first strategy based on bulk doping, graphite/epoxy composite electrode (GECE) bulk was modified with six types of metal ion which were prepared through a wet impregnation procedure. In the second strategy, immobilization of redox dye on carbon cloth and graphite sheet was carried out using N,N′-dicyclohexylcarbodiimide for surface modification. Crystallinity, morphology, surface chemistry and electrochemical properties of all modified electrodes were investigated. Influence of redox behavior of electrodes suited to microbial metabolism and conducive to biofilm formation have been examined. It was observed that the Fe3+ doped GECE surfaces exhibited significantly high biofilm formation of 1.10(±0.18) × 107 CFU/cm2 as compared to other dopants. The microbial growth on the carbon cloth electrode and carbon fiber reinforced plate were found to be less (2.6(±0.97) × 104, 4.8(±1.8) × 103 CFU/cm2 respectively) compared to GECEs. 相似文献
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R. Fröhlich A. Rpzany J. Riedmüller A. Bolz M. Schaldach 《Journal of materials science. Materials in medicine》1996,7(7):393-397
Electrophysiologic examinations as well as the electrotherapy of heart diseases require electrodes which distinguish themselves by outstanding sensing and pacing performance. Both, the sensing and the stimulation behaviour are determined by the interface between electrode and tissue. To avoid energy losses and distortions of heart signals having components down to 1 Hz, the interface's impedance has to be very small in the corresponding frequency range. Towards this goal a new coating has been developed: electrolytically deposited electroactive iridium oxide. On the electrode's surface iridium oxide forms a long-term stable reversible redox system which changes its oxidation state according to the applied potential. The decrease of impendance is demonstrated by impedance spectroscopy: the low-frequency limit is lowered by more than three orders of magnitude to a value of 0.4 Hz. The reason is the electroactivity of this material which is caused by reversible proton incorporation into the coating, as is proven by cyclic voltammetry. Due to the low interface impedance well below 1 Hz, the coated electrodes fulfil the requirements for medical applications. Outstanding sensing behaviour was shown by measuring the monophasic action potential in dogs, which is possible without any distortions.This paper was accepted for publication after the 1995 Conference of the European Society of Biomaterials, Oporto, Portugal, 10–13 September. 相似文献
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Carbon nanotube purification: preparation and characterization of carbon nanotube paste electrodes 总被引:1,自引:0,他引:1
Valentini F Amine A Orlanducci S Terranova ML Palleschi G 《Analytical chemistry》2003,75(20):5413-5421
Paste electrodes have been constructed using single-wall carbon nanotubes mixed with mineral oil. The electrochemical behavior of such electrodes prepared with different percentages of carbon nanotubes has been compared with that of graphite paste electrodes and evaluated with respect to the electrochemistry of ferricyanide with cyclic voltammetry. Carbon nanotubes were purified by a treatment with concentrated nitric acid, then oxidized in air. In addition, electrochemical pretreatments were carried out to increase the selectivity of carbon nanotube electrodes. Performances of carbon nanotube paste and carbon paste electrodes were evaluated by studying such parameters as current peak, deltaEp, anodic and cathodic current ratio, and charge density toward several different electroactive molecules. Data interpretation based on the carbon nanotubes and carbon surface area is presented. Carbon nanotube paste and carbon paste electrodes were tested as H2O2 and NADH probes, and several analytical parameters were evaluated. The oxidative behavior of dopamine was examined at these electrodes. The two-electron oxidation of dopamine to dopaminequinone showed an excellent reversibility in cyclic voltammetry that was significantly better than that observed at carbon paste electrodes. 相似文献
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In this investigation, carbon nanotube (CNT) reinforced aluminum composites were prepared by the molecular-level mixing process using copper coated CNTs. The mixing of CNTs was accomplished by ultrasonic mixing and ball milling. Electroless Cu-coated CNTs were used to enhance the interfacial bonding between CNTs and aluminum. Scanning electron microscope analysis revealed the homogenous dispersion of Cu-coated CNTs in the composite samples compared with the uncoated CNTs. The samples were pressureless sintered under vacuum followed by hot rolling to promote the uniform microstructure and dispersion of CNTs. In 1.0 wt.% uncoated and Cu-coated CNT/Al composites, compared to pure Al, the microhardness increased by 44% and 103%, respectively. As compared to the pure Al, for 1.0 wt.% uncoated CNT/Al composite, increase in yield strength and ultimate tensile strength was estimated about 58% and 62%, respectively. However, in case of 1.0 wt.% Cu-coated CNT/Al composite, yield strength and ultimate tensile strength were increased significantly about 121% and 107%, respectively. 相似文献
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A novel method has been developed for the fabrication of carbon fiber cone nanometer-size ultramicroelectrodes (nanoelectrodes) with overall tip dimensions as small as 50 nm in diameter. In this method, carbon fibers were initially etched by an argon ion beam thinner. Afterward, a single etched carbon fiber was inserted into a glass capillary, which was then sealed by heating the glass/fiber interface in a vacuum; thus, no epoxy resin is involved. The success rate of our fabrication route for the electrodes with overall tip diameters of up to 500 nm was about 80%; for those with tip diameters of up to 100 nm, it was about 50%. The fabricated carbon fiber cone nanoelectrodes (CFCNEs) were inspected by optical and scanning electron microscopy. Their electrochemical behavior was examined by cyclic and linear sweep voltammetric measurements of ferricyanide and ferrocene ions in aqueous and nonaqueous media. The potential analytical applicability of the CFCNEs was tested by differential pulse voltammetric measurements of two well-known neurotransmitters, dopamine (DA) and 5-hydroxytryptamine (5-HT), and the results achieved were highly satisfactory. The calibration plots obtained were linear over the ranges from 5.0 × 10(-7) to 1.0 × 10(-4) and from 2.0 × 10(-6) to 1.0 × 10(-4) mol/L, with limits of detection of 1.0 × 10(-7) and 5.0 × 10(-7) mol/L for DA and 5-HT, respectively. Some advantages and improvements of the proposed CFCNE fabrication method, especially with respect to smoothness of the fiber (electrode) surface, strength, and control over the fiber tip dimensions, are also discussed. 相似文献
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Growth of vertical, multiwalled carbon nanotubes (CNTs) on bulk copper foil substrates can be achieved by sputtering either Ni or Inconel thin films on Cu substrates followed by thermal chemical vapor deposition using a xylene and ferrocene mixture. During CVD growth, Fe nanoparticles from the ferrocene act as a vapor phase delivered catalyst in addition to the transition metal thin film, which breaks up into islands. Both the thin film and iron are needed for dense and uniform growth of CNTs on the copper substrates. The benefits of this relatively simple and cost effective method of directly integrating CNTs with highly conductive copper substrates are the resulting high density of nanotubes that do not require the use of additional binders and the potential for low contact resistance between the nanotubes and the substrate. This method is therefore of interest for charge storage applications such as double layer capacitors. Inconel thin films in conjunction with Fe from ferrocene appear to work better in comparison to Ni thin films in terms of CNT density and charge storage capability. We report here the power density and specific capacitance values of the double layer capacitors developed from the CNTs grown directly on copper substrates. 相似文献
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ARUP DASGUPTA AKASH SINGH PRADYUMNA KUMAR PARIDA R RAMASESHAN P KUPPUSAMI S SAROJA M VIJAYALAKSHMI 《Bulletin of Materials Science》2011,34(3):483-489
The growth characteristics of titanium films deposited on glass, silicon (100) and oxygen free high purity copper substrate
using magnetron sputtering have been investigated using X-ray diffraction, electron microscopy and scratch indentation techniques.
The study of interface between the titanium film and the substrate was carried out to determine coating thickness, as well
as intermixing of the elements at the interface. Studies revealed that the interface is free from voids and intermixing of
the film and the substrate. Microstructural and diffraction analysis showed that the Ti coating was polycrystalline and exhibited
columnar growth. The Ti crystallite size varied between 24 and 58 nm depending on the substrate. The thickness of the films
were typically about 4 μm. Scratch test indicated that the films are adherent and the first critical load to failure was observed
to be 4·5 N ± 2 N. 相似文献
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Preliminary results of diamond-like carbon (DLC) coating with its novel properties with no toxicity have caused a strong interest
of commercial manufacturers of surgical implants. DLC coatings were prepared on polymethylmethacrylate (PMMA) at room temperature
using ion beam assisted deposition (IBAD). It could be shown by X-ray photoelectron spectroscopy, Auger electron spectroscopy,
and Raman spectroscopy that DLC coating prepared by 800 eV CHn+ beam bombardment possessed a higher fraction ofsp
3 bonds in the structure of mixedsp
n3 +sp
n2 bonding, resulting in a higher hydrophobicity. The results of the cell attachment tests indicated that DLC coatings exhibited
low macrophage attachment and provided desirable surface for the normal cellular growth and morphology of the fibroblasts.
At the same time, the number of both neutral granulocytes and platelets adhering to DLC coatings decreased significantly.
These findings showed that DLC was a better coating with desirable tissue and blood compatibility. 相似文献
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Preliminary study of iridium coating on carbon/carbon composites 总被引:5,自引:0,他引:5
Iridium coating was deposited on as-received, polished and chemical vapour deposited (CVD) pyro carbon-coated carbon/carbon composite by d.c. sputtering. The as-received surface of the carbon/carbon composite was not fully covered by an iridium coating up to 12 m thick, whereas better deposition and surface coverage with the iridium coating were obtained on the polished surface and CVD pyro carbon-coated carbon/carbon composite surface. After heat treatment at 2000 K for 1.2 ks, interconnected islands of iridium were formed on three surfaces of the carbon/carbon composite. Iridium neither reacted with nor dissolved the carbon/carbon composite, it had some penetration but did not react to form an interfacial compound, and the boundary between the iridium and carbon/carbon composite was distinct. 相似文献
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Hernández-Santos D Díaz-González M González-García MB Costa-García A 《Analytical chemistry》2004,76(23):6887-6893
Voltammetric enzyme genosensors on streptavidin-modified screen-printed carbon electrodes (SPCEs) for the detection of virulence nucleic acid determinants of pneumolysin and autolysin genes, exclusively present on the genome of the human pathogen Streptococcus pneumoniae, were described. Alkaline phosphatase (AP) and 3-indoxyl phosphate were used as the enzymatic label and substrate, respectively. The oligonucleotide probes were immobilized on electrochemically pretreated SPCEs through the streptavidin/biotin reaction. The adsorption of streptavidin was performed by deposition of a drop of a streptavidin solution overnight at 4 degrees C on the surface of the SPCEs. After the hybridization reaction with FITC-labeled complementary targets, the enzyme is captured using an anti-FITC antibody conjugated to AP. In nonstringent experimental conditions, these genosensors can detect 0.49 fmol of 20-mer oligonucleotide target and discriminate between a complementary oligo and an oligo with a three-base mismatch. In the presence of 25% formamide in the hybridization buffer, a single-base mismatch on the oligonucleotide target can be detected. 相似文献
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AbstractWe introduce a novel strategy of fabricating nanoporous carbons loaded with different amounts of CuO nanoparticles via a hard templating approach, using copper-containing mesoporous silica as the template and sucrose as the carbon source. The nature and dispersion of the CuO nanoparticles on the surface of the nanoporous carbons were investigated by x-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and high-resolution transmission electron microscopy (HRTEM). XRD results reveal that nanoporous carbons with embedded CuO nanoparticles exhibit a well-ordered mesoporous structure, whereas the nitrogen adsorption measurements indicate the presence of excellent textural characteristics such as high surface area, large pore volume and uniform pore size distribution. The amount of CuO nanoparticles in the nanochannels of the nanoporous carbon could be controlled by simply varying the Si/Cu molar ratio of the mesoporous silica template. Morphological characterization by SEM and TEM reveals that high-quality CuO nanoparticles are distributed homogeneously within the nanoporous carbon framework. The supercapacitance behavior of the CuO-loaded nanoporous carbons was investigated. The material with a small amount of CuO in the mesochannels and high surface area affords a maximum specific capacitance of 300 F g-1 at a 20 mV s-1 scan rate in an aqueous electrolyte solution. A supercapacitor containing the CuO-loaded nanoporous carbon is highly stable and exhibits a long cycle life with 91% specific capacitance retained after 1000 cycles. 相似文献
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《Vacuum》1999,52(1-2):193-198
With a titanium interlayer, adherent diamond coating on copper is obtained. The diamond nucleation density is enhanced significantly by scratching the substrate with diamond powder and is influenced by the deposition conditions. It is found that the diamond growth rate increases with microwave power, gas pressure and methane concentration. However, a higher methane concentration results in increased growth defects and non-diamond phases. Under typical deposition conditions, the diamond crystals exhibit a (111) face dominating. The coating adhesion is accessed by pull-off tests and scratch tests. The former indicates that the coating adhesion is better than the strength of the adhesive, at ca 13 MPa. The latter shows a critical load about 8 N. 相似文献