Heat Conductivity of Carbon Nanotubes

The transport of heat through a solid is mainly effected by low frequency phonons. Hence the heat conductivity along the axis of a carbon nanotube can be described as the sum of all phonon states and their respective heat capacity Cph  

Another aspect of the structure must by all means be regarded when discussing the reactivity of real nanotubes Contrary to the ideal tubes considered so far, the ones actually produced by the methods described in Section 3.3 contain defects, sometimes even many of them. These defects may be, for example, holes in the side wall bearing sp hybridized carbon atoms around their rim. The latter may either be saturated with functional groups or they may exist as dangling bonds. The reactivity of the respective nanotube is markedly increased at these positions. 

In principle, the aforementioned considerations hold true for both single-and multiwalled nanotubes. The reactivity of both types differs mostly due to the 

Furthermore, there are interactions between neighboring walls within a multi-walled tube that cause an additional stabilization. Still it is no serious problem to derivatize multiwalled carbon nanotubes as well. In doing so, one takes advantage of the increased reactivity at the tubes ends and of the vulnerability of defect sites in the outer wall of the MWNT. 

The electronic structure of nanotubes naturally influences their chemical behavior, too. Provided electrons close to the Fermi level are involved, the reactivity is expected to differ for all variants metalHc as well as semiconducting, either with small or with large bandgap. The exact position of the Fermi level, however, is largely dependent on the type and position of defects in the carbon lattice, so there is no simple correlation to be observed experimentally. Yet it has turned out in the course of time that certain reactions exhibit remarkable selectivity for specific types of nanotubes. These include, among others, the reaction with diazonium salts and the photochemical osmylation. 

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Hida S, Shiga T, Maruyama S, Elliott JA, Shiomi J (2012) Influence of thermal boundary resistance and interfacial phonon scattering on heat conduction of carbon nanotube/polymer composites. Trans Jpn Soc Mech Eng Part B 78(787) 634-643 Hilmi Y, Seyhana TA, Servet T, Metin T, Wolfgang B, Karl S (2010) Electric field effects on CNTs/vinyl ester suspensions and the resulting electrical and thermal composite properties. Compos Sci Technol 70(14) 2102-2110... 

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