Application of Carbon Nanotubes

Application of speed of light Na nonubesI depart be examining and questioning speed of light na nonubes and the application within industry, I will look at the History and manufacture of blow nanotubes. I will Examine and discuss their chemical substance and physical properties and how these properties make them intakeful in a coarse range of applications.The tale of coke nanotubes is not entirely clear unconstipated for those in the science in that locationfore giving proper credit to the person that invented the elementic number 6 nanotube has been the subject of several risque tech debates among the scientific communities. The initial news report of nanotubes started in the 1970s. A preparation of the planned carbon filaments was completed by Morinobu Endo who was earning his Ph.D. at the University of Orleans, France. The growth of these carbon filaments were initially archetype to be the freshman carbon nanotubes. However, they failed to meet the measurement requirements for width and hence were deemed, eventually, barrelenes. This was still a highly of the essence(p) development in the history of carbon nanotubes, solely it bonny wasnt the right time to be considered the front near recognized foundation. Giving the proper credit to who invented carbon nanotubes would not muster along for another 20 years. In 1991 the true initiatory invention of nanotube was finally made. It seems as though there was a speed up between Russian nanotechnologists and Sumio Iijima of IBM. The first observation of the multiwall carbon nanotubes was attribute to Iijima. on that point atomic number 18 some that hold the belief that in the 1950s there was an initial discovery of what could baffle possibly been seen as the first carbon nanotubes had Roger Bacon had the high powered electron microscope that would have been necessary. He was credited with the first visual impression of the tubes of subdivisions that roll up and are capped with full erene molecules by many scientists in the field. Some state that his discovery just wasnt taken very seriously at the time be excite science did not accredit how this discovery could impact scientific research.It would be in 1993 that Iijima and Donald Bethune found atomic number 53 walled nanotubes known as buckytubes. This helped the scientific community make more understanding out of not only the potency for nanotube research, but the use and existence of fullerenes. With this in instituteation, the complete discovery of carbon nanotubes was realized and Iijima and Bethune were ultimately credited with their discovery in their entirety. Russian nanotechnologists were independently discovering the same visual affirmation. They were just a little bit later in their announcement and the potential effect of this discovery.While Roger Bacon might not have been completely advised of the impact his discovery had on the scientific world, he is technically the first scientist to dis cover these hollow tubes of carbon that are changing lives on a daily basis. Since the initial rediscovery of the nanotubes in 1991, who discovered carbon nanotubes is no weeklong as important as who can come up with the almost practical applications.DefinitionCarbon nanotubes are large molecules of pure carbon that are long and thin and shaped like tubes, about 1-3 nanometres (1 nm = 1 ordinal of a meter) in diameter, and hundreds to thousands of nanometres long.A carbon nanotube (CNT) is a toy dog rounded carbon structure that has hexagonal plumbago molecules attached at the edges. Nanotubes look like a powder or black soot, but theyre actually rolled-up sheets of graphene that form hollow strands with walls that are only one atom thick. Nanotubes, which are sometimes called buckytubes, were developed from the Fullerene, a structure that is similar to the geodesic domes.Nanotubes can be characterized by their number of concentric cylinders, cylinder rung and cylinder length . Some nanotubes have a home called chirality, an expression of longitudinal twisting. Multiple nanotubes can be assembled into microscopic mechanical systems called nanomachines.ShapesAlthough carbon nanotubes are intemperate, they are not brittle. They can be bent, and when released, they will spring back off to their original shape.One type of carbon nanotube has a cylindrical shape with open ends.Another type of nanotube has closed ends, make by some of the carbon atoms combining into pentagons on the end of the nanotube. formula 3.2 A carbon nanotube with closed endsCarbon nanotubes can come as multiple concentric cylinders of carbon atoms, called multi-walled carbon nanotubes (MWCTs). Logically enough, carbon nanotubes that have only one cylinder are called single-walled carbon nanotubes. leash orientations are possible armchair, zigzag, and chiral.Figure 3.3 The three possible orientations of CNTsChemical PropertiesCarbon nanotubes are polymers of pure carbon, and thus possess all of carbons versatility, including the ability to form countless combinations and derivatives. In addition, carbon nanotubes are direct beneficiaries of the rich history and vast body of knowledge associated with carbon chemistry. Consequently, carbon nanotubes can be functionalized in countless ways employ a variety of easy-understood chemical reactions. In addition, the geometry of a nanotube allows for the formation of novel synthetic structures not possible with other carbon structures. Carbon nanotubes can be derived twain covalently, in which other molecules being bonded to the nanotube share an electron with the tube, and non-covalently, in which the other molecule simply adheres to the carbon nanotubes sidewall, providing a nano-scale coating of the carbon nanotube. Because the carbon nanotube sidewalls are electrically polarizable, polar molecules can advantageously adhere to their surfaces. When molecules adhere even non-covalently to the carbon nanotube sur face, they often cause subtle changes in the electronic structure of the tubes. Such changes can be easily detected, making carbon nanotubes exquisitely sensitive chemical sensors. An important aspect of non-covalent derivatization is the association of surfactants with the carbon nanotube surface, enabling them to be hang in water.Physical PropertiesElectricalThere has been considerable practical delight in the admitivity of CNTs. CNTs with particular combinations of N and M (structural parameters indicating how more the nanotube is twisted) can be highly conducting, and hence can be say to be metallic. Their conductivity has been shown to be a function of their chirality (degree of twist), as well as their diameter. CNTs can be either metallic or semi-conducting in their electrical behaviour. Conductivity in MWNTs is quite complex. Some types of armchair-structured CNTs appear to conduct better than other metallic CNTs. Furthermore, interwall reactions within MWNTs have been found to redistribute the current over individual tubes non-uniformly. However, there is no change in current across different parts of metallic single-walled CNTs. However, the behaviour of ropes of semi-conducting SWNTs is different, in that the transport current changes abruptly at various positions on the CNTs. The conductivity and resistance of ropes of SWNTs has been measured by placing electrodes at different parts of the CNTs. The resistivity of the SWNT ropes was in the order of 10-4 ohm-cm at 27C. This means that SWNT ropes are the most conductive carbon fibres known. The current density that was possible to achieve was 107 A/cm2, however in theory the SWNT ropes should be able to sustain much higher stable current densities, as high as 1013 A/cm2. It has been reported that individual SWNTs may contain defects. Fortuitously, these defects allow the SWNTs to act as transistors. Likewise, joining CNTs together may form transistor-like devices. A nanotube with a natural jun ction (where a straight metallic section is get together to a chiral semiconducting section) behaves as a rectifying diode that is, a half-transistor in a single molecule. It has in like manner novelly been reported that SWNTs can road electrical signals at high speeds (up to 10 GHz) when used as interconnects on semi-conducting devices.Strength and elasticityThe carbon atoms of a single (graphene) sheet of graphite form a planar honeycomb lattice, in which each atom is connected via a strong chemical bond to three neighbouring atoms. Because of these strong bonds, the basal-plane elastic modulus of graphite is one of the largest of any known material. For this reason, CNTs are pass judgment to be the ultimate high-strength fibres. SWNTs are derisoryer than steel, and are very resistant to prostitute from physical forces. Pressing on the tip of a nanotube will cause it to bend, but without damage to the tip. When the force is removed, the tip returns to its original state. T his property makes CNTs very useful as probe tips for very high-resolution examine probe microscopy. Quantifying these effects has been rather difficult, and an exact numerical range has not been agreed upon. Using an atomic force microscope (AFM), the unanchored ends of a freestanding nanotube can be pushed out of their equilibrium position and the force needed to push the nanotube can be measured. The current Youngs modulus value of SWNTs is about 1 TeraPascal, but this value has been disputed, and a value as high as 1.8 Tpa has been reported. Other values significantly higher than that have also been reported. The differences probably arise through different experimental measurement techniques. Others have shown theoretically that the Youngs modulus depends on the size and chirality of the SWNTs, ranging from 1.22 Tpa to 1.26 Tpa. They have calculated a value of 1.09 Tpa for a generic nanotube. However, when working with different MWNTs, others have noted that the modulus meas urements of MWNTs using AFM techniques do not strongly depend on the diameter. Instead, they argue that the modulus of the MWNTs correlates to the centre of disorder in the nanotube walls. Not surprisingly, when MWNTs break, the outermost layers break first.thermic ConductivityNew research from the University of Pennsylvania indicates that CNTs may be the top hat heat-conducting material man has ever known. Ultra-small SWNTs have even been shown to exhibit superconductivity downstairs 20oK. Research argues that these exotic strands, already heralded for their unparalleled strength and singular ability to adopt the electrical properties of either semiconductors or perfect metals, may someday also find applications as miniature heat conduits in a host of devices and materials. The strong in-plane graphitic C-C bonds make them exceptionally strong and stiff against axial strains. The almost zero in-plane thermic expansion but large inter-plane expansion of SWNTs implies strong in- plane coupling and high flexibility against non-axial strains. Many applications of CNTs, such(prenominal) as in nanoscale molecular electronics, sensing and actuating devices, or as reinforcing additive fibres in functional composite materials, have been proposed. Reports of several recent experiments on the preparation and mechanical characterization of CNT-polymer composites have also appeared. These measurements suggest modest enhancements in strength characteristics of CNT-embedded matrixes as compared to bare polymer matrixes. Preliminary experiments and simulation studies on the thermal properties of CNTs show very high thermal conductivity. It is expected, therefore, that nanotube reinforcements in polymeric materials may also significantly improve the thermal and thermo-mechanical properties of the composites.