Structure of Multiwalled Carbon Nanotubes

MultiwaUed carbon nanotubes (MWNT) consist of a concentric arrangement of single-walled nanotubes with a usually constant distance of layers. There are examples with just two nanotubes fit one into another (so alled double-walled nanotubes, DWNTs) as well as species with many shells (more than 50). The latter measure many nanometers in diameter and may be so hard to distinguish from classical carbon fibers that only electron microscopy can reveal the difference. Common MWNTs, however, possess a smaller number of concentric tubes. The nomenclature of MWNT indicates the intercalation of the inner tubes by the notation (wi,mi) (n2,m2i (n3,m3) .starting from the central tube. 

Usually a cyUndrical void is found in the core of these tubes. Its diameter may be anything from Inm to several nanometers. The smallest possible hollow is determined by the size of the innermost SWNT, so diameters less than about 

2 nm are rather unlikely to be found. The hitherto existing experimental results confirm this (although there are reports on SWNT with a diameter of 0.4 run only). An upper limit to the size of the cavity theoretically does not exist However, structures with very large hoUows are increasingly unstable and, consequently, not very probable. Typical inner diameters of nanotubes with about 10 shells amount to several nanometers. 

In principle, the same rules apply to the atomic construction of multiwalled nanotubes like they do to single-walled species. This is consequent as the first 

The structure of normal MWNT will be considered here to begin with- normal meaning those with a constant distance between individual layers. This bears several consequences for the stmcture. An ABAB-sequence of layers like in graphite, for instance, can be maintained in very small areas only. The individual tubes are rather disorderly shoved one into another, rendering a direct interaction close to impossible. The reason of this effect is the introduction of additional carbon atoms into the lattice of the outer tubes. It is required because at a distance of 

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Cell viability, adhesion and proliferation Fibrous structures of multiwalled carbon nanotubes and polyurethane composites with average fiber diameters of 300-500 nm were fabricated via electrospinning. These MWNT-incorporated scaffolds exhibited high enhancement on cell adhesion, proliferation, migration, and aggregation. Meng et al. Composition... 

Petersen, E.J., Lam, T., Gorham, J.M., Scott, K.C., Long, C.J., Stanley, D., Sharma, R., Alexander Liddle, J., Pellegrin, B., Nguyen, T. Methods to assess the impact of UV irradiation on the surface chemistry and structure of multiwall carbon nanotube epoxy nanocomposites. Carbon 69, 194—205 (2014)... 

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