Multiwalled carbon nano tube

Figure 1. Schematic diagram of a single-wall carbon nanotube (SWNT) (a) and a multiwall carbon nano tube (MWNT) (b). Adapted from Reference 10.

Ruan, S., Gao, P. and Yu, T. X. Ultra-strong gel-spun UHMWPE fibers reinforced using multiwalled carbon nano tubes. Polymer 1006, 47 1604-11. 

Kim, B. Sigmund, W. M. Functionalized multiwall carbon nano-tube/gold nanoparticle composites. Langmuir 20, 8239-8242 (2004). 

Potschke P, Fomes TD, Paul DR (2002) Rheological behavior of multiwalled carbon nano-tube/polycarbonate composites. Polymer 43 3247-3255... 

By applying cationic polymerization of tetrahydrofuran starting from the carbonyl chloride group-functionalized multiwalled carbon nano tubes (MWNT) with silver perchlorate as a catalyst poly-THF was chemically anchored to MWNT surfaces affecting their properties. 

Carbon nanotubes are hollow carbon structures as a graphite sheet wound cylindrically. Their diameter is few A to 100 nm. Since the aspect ratio is very large, the material has a fibrous form. Carbon nanotubes having one graphite layer are called SWCNT (Single-Walled Cabon Nanotube). Other carbon nano tubes are called MWCT (Multiwalled Carbon Nano tube) (lijima 1991 Saito 2003 Fan et al. 1999 Nakayama 2002 Akita et al. 2001). 

The reaction with azomethine yUdes is a typical [3+2]-cycloaddition. It leads to the products shown in Figure 3.74b. The reaction is particularly suitable to couple biologically active moieties to carbon nanotubes, which is of great relevance, for example, for the preparation of nanotube-peptide composites. The reaction is normally performed on a nano tube suspension in DMF that is treated with an N-substituted glycine and paraformaldehyde or with an aldehyde carrying a further residue to be coupled. The azomethine ylide is then formed in situ it constitutes the actual reagent. The method is appUcable to single- and multiwalled nanotubes. 

Single- and multiwalled carbon nanotubes represent attractive components for supramolecular structures. Their rod shape predestines them as guest molecules to be included inside host compounds that are designed like rings or hollow cylinders. From an arrangement with the host wrapped helically around the nano-tube, another type of supramolecular compound arises. The tubes can further serve as scaffold to supramolecular structures that form by a complexation of single tubes or bundles. Several examples of supramolecular patterns have already been discussed in Section 3.5.4.2 on the noncovalent functionalization of nano-tubes. Hence only some other specimens will be presented here. 

Carbon nanotubes are one of the most important classes of new carbon materials. Distinctions are made between single- and multiwalled as well as between zig-zag, armchair, and chiral nanotubes. The structure is characterized by the descriptors n and m. These structural parameters allow for a prediction of the electric conductivity. Only armchair nano tubes n,n) and such species with m-n = iq are electric conductors. Any other nanotube is semiconducting. These statements have been established from symmetry considerations and from determining the band structure by way of the zone-folding method. There are different approaches to the production of single- and multiwalled nanotubes. Important methods of preparation are ... 

Andrews R, Jacques D, Minot M and Rantell T (2002) Fabrication of carbon multiwall nano-tube/polymer composites by shear mixing, Macromol Mater Eng 287 395-403. 

---