Carbon Nanotubes--the Route Toward Applications
02 Aug 2002-Science (American Association for the Advancement of Science)-Vol. 297, Iss: 5582, pp 787-792
TL;DR: Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects.
Abstract: Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects. Some of these applications are now realized in products. Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded by controversy. Nanotube cost, polydispersity in nanotube type, and limitations in processing and assembly methods are important barriers for some applications of single-walled nanotubes.
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TL;DR: In this paper, a new type of vitrimers (BDSER) based on thermosetting dynamic epoxy network with double disulfide bonds was synthesized by the reaction of a difunctional epoxy monomer containing disulfides bonds with 4,4′-disulfanediyldianiline (4-AFD).
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TL;DR: A highly sensitive and label-free amperometric immunosensor developed for the detection of carcinoembryonic antigen (CEA) based on layer-by-layer assembly of gold nanoparticles, multi-walled carbon nanotubes-thionine and chitosan on gold electrode surface by electrostatic adsorption showed an excellent reproducibility and stability.
119 citations
TL;DR: In vivo and in vitro studies demonstrate that MWCNTs stimulate pulmonary fibrotic responses such as fibroblast proliferation and collagen deposition in a TGF-β/Smad-dependent manner and suggest that tube length acts as an important factor in M WCNT-induced macrophage activation and subsequent TGF -β1 secretion.
Abstract: Multiwall carbon nanotubes (MWCNTs) have been widely used in many disciplines due to their unique physical and chemical properties, but have also raised great concerns about their possible negative health impacts, especially through occupational exposure Although recent studies have demonstrated that MWCNTs induce granuloma formation and/or fibrotic responses in the lungs of rats or mice, their cellular and molecular mechanisms remain largely unaddressed Here, it is reported that the TGF-beta/Smad signaling pathway can be activated by MWCNTs and play a critical role in MWCNT-induced pulmonary fibrosis Firstly, in vivo data show that spontaneously hypertensive (SH) rats administered long MWCNTs (20-50 mu m) but not short MWCNTs (05-2 mu m) exhibit increased fibroblast proliferation, collagen deposition and granuloma formation in lung tissue Secondly, the in vivo experiments also indicate that only long MWCNTs can significantly activate macrophages and increase the production of transforming growth factor (TGF)-beta 1, which induces the phosphorylation of Smad2 and then the expression of collagen I/III and extracellular matrix (ECM) protease inhibitors in lung tissues Finally, the present in vitro studies further demonstrate that the TGF-beta/Smad signaling pathway is indeed necessary for the expression of collagen III in fibroblast cells Together, these data demonstrate that MWCNTs stimulate pulmonary fibrotic responses such as fibroblast proliferation and collagen deposition in a TGF-beta/Smad-dependent manner These observations also suggest that tube length acts as an important factor in MWCNT-induced macrophage activation and subsequent TGF-beta 1 secretion These in vivo and in vitro studies further highlight the potential adverse health effects that may occur following MWCNT exposure and provide a better understanding of the cellular and molecular mechanisms by which MWCNTs induce pulmonary fibrotic reactions
119 citations
TL;DR: Template pre-organized oligopeptides were conjugated to poly(ethylene oxide) chains yielding peptide-polymer-building blocks that self assemble into fiber-like nanostructures having a maximum length in the range of a micrometer.
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TL;DR: This review examines the different possibilities of HP-based nanoparticle composites and their medicinal or biological applications.
Abstract: The combination of nanoparticles and biological molecules is of intense interest because of the synergistic properties offered by such newly synthesized composites. Heparin (HP), conjugated to nanomaterials, has recently been investigated for its chemical and biological properties. HP has a number of biological activities that can be enhanced when composited with nanoparticles. In addition, HP improves the biocompatibility of nanoparticles improving their performance in various biological applications. A variety of recent research combines HP and nanomaterials for a myriad of applications. HP has been conjugated to the surface of the nanoparticles, such as magnetic and metallic nanoparticles, or biodegradable and nondegradable synthetic polymers. HP has also been incorporated into the nanoparticles. There are numerous possibilities for material composites and chemistries that incorporate HP. This opens the door for novel applications ranging from improving anticoagulant activity, for anticancer and antitumor therapy, to tissue engineering and biosensors. This review examines the different possibilities of HP-based nanoparticle composites and their medicinal or biological applications.
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References
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TL;DR: The nanotubes sensors exhibit a fast response and a substantially higher sensitivity than that of existing solid-state sensors at room temperature and the mechanisms of molecular sensing with nanotube molecular wires are investigated.
Abstract: Chemical sensors based on individual single-walled carbon nanotubes (SWNTs) are demonstrated. Upon exposure to gaseous molecules such as NO 2 or NH 3 , the electrical resistance of a semiconducting SWNT is found to dramatically increase or decrease. This serves as the basis for nanotube molecular sensors. The nanotube sensors exhibit a fast response and a substantially higher sensitivity than that of existing solid-state sensors at room temperature. Sensor reversibility is achieved by slow recovery under ambient conditions or by heating to high temperatures. The interactions between molecular species and SWNTs and the mechanisms of molecular sensing with nanotube molecular wires are investigated.
5,908 citations
TL;DR: In this paper, the fabrication of a three-terminal switching device at the level of a single molecule represents an important step towards molecular electronics and has attracted much interest, particularly because it could lead to new miniaturization strategies in the electronics and computer industry.
Abstract: The use of individual molecules as functional electronic devices was first proposed in the 1970s (ref 1) Since then, molecular electronics2,3 has attracted much interest, particularly because it could lead to conceptually new miniaturization strategies in the electronics and computer industry The realization of single-molecule devices has remained challenging, largely owing to difficulties in achieving electrical contact to individual molecules Recent advances in nanotechnology, however, have resulted in electrical measurements on single molecules4,5,6,7 Here we report the fabrication of a field-effect transistor—a three-terminal switching device—that consists of one semiconducting8,9,10 single-wall carbon nanotube11,12 connected to two metal electrodes By applying a voltage to a gate electrode, the nanotube can be switched from a conducting to an insulating state We have previously reported5 similar behaviour for a metallic single-wall carbon nanotube operated at extremely low temperatures The present device, in contrast, operates at room temperature, thereby meeting an important requirement for potential practical applications Electrical measurements on the nanotube transistor indicate that its operation characteristics can be qualitatively described by the semiclassical band-bending models currently used for traditional semiconductor devices The fabrication of the three-terminal switching device at the level of a single molecule represents an important step towards molecular electronics
5,258 citations
TL;DR: X-ray diffraction and electron microscopy showed that fullerene single-wall nanotubes (SWNTs) are nearly uniform in diameter and that they self-organize into “ropes,” which consist of 100 to 500 SWNTs in a two-dimensional triangular lattice with a lattice constant of 17 angstroms.
Abstract: The major part of this chapter has already appeared in [1], but because of the length restrictions (in Science), the discussion on why we think this form is given in only brief detail. This chapter goes into more depth to try to answer the questions of why the fullerenes form themselves. This is another example of the very special behavior of carbon. From a chemist’s standpoint, it is carbon’s ability to form multiple bonds that allows it to make these low dimensional forms rather than to produce tetrahedral forms. Carbon can readily accomplish this and it is in the mathematics and physics of the way this universe was put together, that carbon is given this property. One of the consequences of this property is that, if left to its own devices as carbon condenses from the vapor and if the temperature range is just right, above 1000°C, but lower than 1400°C, there is an efficient self-assembly process whose endpoint is C60.
5,215 citations
TL;DR: In this paper, the Young's modulus, strength, and toughness of nanostructures are evaluated using an atomic force microscopy (AFM) approach. And the results showed that the strength of the SiC NRs were substantially greater than those found previously for larger SiC structures, and they approach theoretical values.
Abstract: The Young's modulus, strength, and toughness of nanostructures are important to proposed applications ranging from nanocomposites to probe microscopy, yet there is little direct knowledge of these key mechanical properties. Atomic force microscopy was used to determine the mechanical properties of individual, structurally isolated silicon carbide (SiC) nanorods (NRs) and multiwall carbon nanotubes (MWNTs) that were pinned at one end to molybdenum disulfide surfaces. The bending force was measured versus displacement along the unpinned lengths. The MWNTs were about two times as stiff as the SiC NRs. Continued bending of the SiC NRs ultimately led to fracture, whereas the MWNTs exhibited an interesting elastic buckling process. The strengths of the SiC NRs were substantially greater than those found previously for larger SiC structures, and they approach theoretical values. Because of buckling, the ultimate strengths of the stiffer MWNTs were less than those of the SiC NRs, although the MWNTs represent a uniquely tough, energy-absorbing material.
4,627 citations
TL;DR: The thermal conductivity and thermoelectric power of a single carbon nanotube were measured using a microfabricated suspended device and shows linear temperature dependence with a value of 80 microV/K at room temperature.
Abstract: The thermal conductivity and thermoelectric power of a single carbon nanotube were measured using a microfabricated suspended device. The observed thermal conductivity is more than 3000 W/K m at room temperature, which is 2 orders of magnitude higher than the estimation from previous experiments that used macroscopic mat samples. The temperature dependence of the thermal conductivity of nanotubes exhibits a peak at 320 K due to the onset of umklapp phonon scattering. The measured thermoelectric power shows linear temperature dependence with a value of 80 microV/K at room temperature.
3,166 citations