Can you make carbon nanotubes at home?
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That finding offered the tantalizing prospect that a haze of graphite whiskers in space could explain why some supernovas appear dimmer, and therefore farther away, than they should be, according to current models. Yet, "very little is known about graphite whisker formation, and so it is difficult to adequately interpret their discovery," says Marc Fries of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Generally, a centrifugal separation is necessary to concentrate the single walled nanotubes in low-yield soot before the micro filtration operation, since the nanoparticles easily contaminate membrane filters. Two models best describe the structure of multi-walled carbon nanotubes, the Russian Doll and Parchment models. (But don’t try it at home—your oven’s not hot enough.) Baking soda, table salt, and detergent are surprisingly effective ingredients for cooking up carbon nanotubes. … Each tube is made from a rolled-up lattice of hexagonally arranged carbon atoms.
Space apparently has its own recipe for making carbon nanotubes, one of the most intriguing contributions of nanotechnology here on Earth, and metals are conspicuously missing from the list of ingredients. It should probably be noted that I don't exactly yet know what it is I'm going to do with carbon nanotubes once I've grown them--in fact, that's an understatement, I have no clue--but that's not likely to stop me here. Maybe I can bribe a hacker with muffins to suck all the air out through a scuba mask regulator...
How can you make carbon nanotubes at home?
There are different types of CNTs, because the graphitic sheets can be rolled in different ways. Within a single wire, insulating and conducting regions may be precisely defined. One-dimensional interconnects engineering becomes realistic with fullerenes. Heory shows that the maximum electrical conductivity is to be expected for endohedral metal atoms, which will transfer three electrons to the fullerene.
The classic chemical techniques for purification have been tried, but they have not been found to be effective in removing the undesirable impurities. Ball milling and subsequent annealing is a simple method for the production of CNTs. Some applications such as super capacitors use a roller to flatten the array to make a conductive layer in the device. Systems with appropriate material inside the fullerene ball are conducting and are of particular interest because they can be deposited to produce bead-like conducting circuits. Only the tangents of the graphitic planes come into contact with each other, and hence their properties are more like those of a molecule. Of course they can also be bonded to fullerenes outside the ball as salts, if the fullerene can gain electrons.
How long does it take to grow carbon nanotubes?
The carbon nanotube’s length is substantially greater than its diameter. Carbon nanotubes are a folded version of the two-dimensional graphene sheet. The family of compounds forms the smallest carbon hoop structure with a set diameter and set orientation of benzene molecules, which are the two variables that determine a nanotube’s electronic properties. Because of this, cycloparaphenylene molecules could be used as seeds or templates to grow large batches of carbon nanotubes with just the right specifications.
Each tube is made from a rolled-up lattice of hexagonally arranged carbon atoms. The bond between carbon atoms is extraordinarily strong, and when patterned into a flat lattice or a tube-shaped lattice , such structures can have exceptional stiffness and strength. In the CVD process, manufacturers can combine a metal catalyst with carbon-containing reaction gases to form carbon nanotubes on the catalyst inside a high-temperature furnace. This has less of an effect on a multi walled carbon nanotube due as the damage is only on the out walls and the inner walls remain in tact. It can have a dramatic effect on mechanical and conductive properties of single walled nanotubes. Typical chemical functional groups are hydroxyl – OH, Carboxyl – COOH, & Amine – NH2.
Why do carbon nanotubes grow?
To synthesize the elusive cycloparaphenylene, the team developed a relatively simple, low-temperature way to bend a string of benzene rings — which normally resist bending — into a hoop. The result is a structure that is as unusual as it is potentially useful. And it’s poised to improve the way one of most promising stars in nanotechnology is produced. Department of Energy User Facility located at Berkeley Lab that provides support to nanoscience researchers around the world.
Like graphene, nanotubes are strong and conduct electricity because they have delocalized electrons. CNTs grow over the catalyst and are collected after the system is cooled to room temperature. The process involves passing a hydrocarbon vapor through a tube furnace where a catalyst material is present at a high enough temperature (600 to 1200°C) to decompose the hydrocarbon. We find that sonicating the mixture for 80% of the total time before adding the surfactant solution can enhance the dispersion effect by first well dispersing the carbon nanotubes prior to the surfacant being added to stabilize it.
The tensile strength of carbon nanotubes is approximately 100 times greater than that of steel of the same diameter. The properties of carbon nanotubes make them ideal for enhancing different kinds of structures – for example, sports equipment, body armour, vehicles, etc., where they are being widely used. The nanotubes create networks within the composite material for instance to increase stiffness and material damping. Graphite powder is immersed in a mixed solution of nitric and sulfuric acid with potassium chlorate.
“Graphene is far superior to carbon nanotubes or any other known nanofiller in transferring its exceptional strength and mechanical properties to a host material.” … The research team also infused epoxy composites with carbon nanotubes. Epoxy materials infused with graphene exhibited far superior performance. One indication of that possibility came in 2008, when the long, thin carbon structures known as graphite whiskers—essentially, bigger cousins of carbon nanotubes—were identified in three meteorites.
You just mix them together and cook it for a few minutes, and you get something that looks like char, but that is nanoparticles with high luminescence. The main method of functionalization is by re-fluxing in concentrated acids under heat. It is important to keep the CNTs well-separated in solution, so the CNTs are typically dispersed using a surfactant prior to the last stage of separation. They can be deposited on substrates, or further manipulated in solution, and can have many different functional groups attached to the ends and sides of the CNTs.
The structure of the nanotube influences its properties – including electrical and thermal conductivity, density, and lattice structure. It is possible to recognize zigzag, armchair, and chiral CNTs just by following the pattern across the diameter of the tubes, and analyzing their cross-sectional structure. When viewed with a transmission electron microscope these tubes appear as planes. Their structure is determined by the specific synthesis conditions which rarely produce a homogeneous product as they are usually mixtures of the different types of CNTs produced in a given reaction. The work also could help researchers understand puzzling observations about some supernovas.
During plasma based purification, certain process gasses are flowed into the plasma reactor which when excited by the energetic plasma forms covalent bonds between the functional groups and the surface of the carbon nanotubes. Research has shown that this method produces more multi walled nanotubes and few single walled nanotubes. Fullerenes and bundles of single walled nanotubes were also found among the multi walled nanotubes produced on the carbon/zeolite catalyst. Thus, under these conditions, the lowest lethal dose is greater than 1000 mg/kg b.w. So feel free to eat all the CNTs you want in lab, assuming they are not functionalized, you do it only once, and you limit yourself to single walled carbon nanotubes. Researchers typically grow CNTs on various materials through a process called chemical vapor deposition.
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