Carbon nanotubes macroscopic shaping

The synthesis of the patterned macroscopic shape consists in the growth of carbon nanotubes in a parallel direction from a fiat substrate surface. This was achieved using a mixture of toluene containing ferrocene compounds or directly with ethylene and steam etching [46-49]. The carbon nanotubes were formed as a thick layer covering the silica reactor wall. The sample could easily be recovered by scratching the dark deposit with a razor blade. 

In summary, the catalytic route provides an interesting way to prepare carbon nanotubes with high yield and selectivity at relatively low synthesis temperature. The easy scale-up of the catalytic method allows one to ensure the mass production of these ID materials with reasonable cost for large scale applications. The development of different methods to produce carbon nanotubes in a controlled macroscopic shape and size, i.e. constraint synthesis, patterned and aligned carbon nanotubes forest by pyrolysis of organic compounds, avoids the formation of fines... 

The morphology of ordered mesostructured carbons is another important factor with respect to their practical applications. Various macroscopic morphologies are required, for example, films (in sensor, separation and optical applications), uniformly sized spheres (in chromatography) or transparent monoliths. Using suitable synthesis strategies, it is possible to control the external shape of the templated mesoporous carbon materials to generate powders, films and membranes, spheres, hollow spheres, rods, fibres, nanowires, nanotubes and monoliths. 

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