Electrical conductivity of carbon nanotubes

Meincke O, Kaempfer D, Weickmann H, Friedrich C, Vathauer M, Warth H (2004). Mechanical properties and electrical conductivity of carbon-nanotube filled polyamide-6 and its blends with acrylonitrile/butadiene/styrene. Polymer 45 739-748. 

The electrical conductance of carbon nanotubes is sensitive to the chemical environment of the tubes. A large difference in the electrical conductance is observed for the carbon nanotubes in the presence of air and oxygen atmosphere. " " It is possible to tune the electrical conductance of carbon nantubes reversibly using adsorbent gas molecules. The carbon nanotubes were also used to increase the conductance of a conjugated polymer for the development of electroluminescence polymer-nanocomposites. " ... 

The electric conductivity of carbon nanotubes is largely influenced by the presence of defects. Even effects as modest as axial strain with bond expansion change the band structure. Stone-Wales defects and other imperfections diminish the electric conductivity as well. This effect is especially pronounced for defects with two adjacent vacancies. The resistance of a 400 nm long SWNT, for example, increases by a factor of 1000 if the tube bears as little as 0.03% of these double vacancies. Single vacancies, on the other hand, do not cause such dramatic changes. In any case, however, the free path of the electrons is reduced considerably by the defects (in parts down to a few nanometers). Still, due to the multitude of existing conduction channels, this has no large influence on the overall conductivity. 

Barrau, S., Demont, R, Perez, E., Peigney, A., Laurent, C., and Lacabanne, C., Effect of palmitic acid on the electrical conductivity of carbon nanotubes-epoxy resin composites. Macromolecules, 36, 9678-9680 (2003b). 

Metal matrix nanocomposites are those having metal as the continuous phase or matrix and other nanoparticles like carbon nanotube as the reinforced materials. These types of composites can be classified as continuous and noncontinuous. One of the more important nanocomposites is Carbon nanotube reinforced metal matrix composite, which is an emerging new material with the high tensile strength and electrical conductivity of carbon nanotube materials. In addition to carbon nanotube metal matrix composites, boron nitride reinforced metal matrix composites and carbon nitride metal matrix composites are the new research areas on metal matrix nanocomposites [9,10]. 

The electrical conductivity of carbon nanotubes in insulating plastics is a topic of considerable interest. The potential applications include electromagnetic... 

The intermediate 19 was synthesized by nucleophilic addition of alkynes to a-hydroxy ketone in the presence of DABCO in dichloromethane at room temperature for 10 minutes. The intermediate 19 provides the furan in the presence of CuO/CNT catalyst in presence of acetic acid in DMF at 60 °C (Scheme 44). During optimization of the reaction conditions it has been foimd that in the presence of several copper (II) and copper (I) salts such as CuBr2, CuCl2, Cu(OAc)2, CuO, CuI, CuBr, CuCl, the reaction gives yields of less than 10%. But in case of CuO/CNT the reaction provides product in higher yield (greater than 60%) in acetic acid. This indicates that the excellent electrical conductivity of carbon nanotubes might promote the cyclization reaction. 

Li, E. Y. and Marzari, N. 2011. Improving the electrical conductivity of carbon nanotube networks A first-principles study. ACS Nano 5 9726-9736. 

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