What are Cabron Nanotubes?

 

Carbon nanotubes (CNTs) are tubes that consist of carbon with diameters typically measured in nanometers. Additionally, carbon nanotubes often refer to single-wall carbon nanotubes (SWCNTs) with diameters in the range of a nanometer. Iijima, Ichihashi and Bethune et al independently discovered them. In carbon arc chambers similar to those used to produce fullerenes. Single-wall carbon nanotubes are one of the allotropes of carbon, intermediate between fullerene cages and flat graphene.

 

Single-Wall Carbon Nanotubes

 

Although not made this way, single-wall carbon nanotubes are like cutouts from a two-dimensional hexagonal lattice of carbon atoms rolled up along one of the Bravais lattice vectors of the hexagonal lattice to form a hollow cylinder. Consequently, in this construction, periodic boundary conditions impose over the length of this roll-up vector to yield a lattice with helical symmetry of seamlessly bonded carbon atoms on the cylinder surface.

Carbon nanotubes also often refer to multi-wall carbon nanotubes (MWCNTs) consisting of nested single-wall carbon nanotubes. If not identical, these tubes are very similar to Oberlin, Endo and Koyama’s long straight and parallel carbon layers cylindrically rolled around a hollow tube. Engineers sometimes use multi-wall carbon nanotubes to refer to double- and triple-wall carbon nanotubes.

 

Paper-Thin Nanotube Speakers

 

In a recent development, researchers in China developed a paper-thin loudspeaker that you can attach to clothing, walls, windows or even insert into the ear. These paper-thin loudspeakers consisted of transparent carbon nanotube films. Subsequently, their work was published in the ACS journal Nano Letters (Fan et al. 2008). So, professor Fan and his research group at Tsinghua University, China developed the smallest loudspeaker of the world using CNT thin films by a simple fabrication process. Today, the loudspeaker s available in the market are bulky and complex. By making these loudspeakers thinner and compact, people can suitably use them for new digital electronic devices and various other applications. Furthermore, engineers already use carbon nanotubes (CNTs)  for various applications including the transmission of sound and music.

Researchers mounted a carbon nanotube film on two electrodes and found that the system works as a loudspeaker. This CNT thin films can generate sound by applying and audio frequency current through it. What’s more, this phenomenon is a result of a thermoacoustic effect. Moreover, the ultra-small heat capacity per unit area of CNT thin films can lead to a wide frequency response range and high sound pressure level. Therefore, this CNT thin film can be a practical magnet-free loudspeaker, which has a very simple structure. The CNT thin film was pulled from a super aligned CNT array grown on a 4-inch silicon wafer and put on two electrodes of a frame to make a loudspeaker.

 

Source Texts

 

https://en.wikipedia.org/wiki/Carbon_nanotube?fbclid=IwAR0SgwbHW5_FgbqnyLQzEMALKdub2VS_3XjoFLzkZ17qS-KuzAQ6NGUgGBc

https://books.google.rs/books?id=ZheaDwAAQBAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false