1. Carbon nanotubes: short overview on the material

A carbon atom has six electrons with two of them filling the 1s orbital. The remaining four electrons fill the sp3 or sp2 as well as the sp hybrid orbital, responsible for bonding structures of diamond, graphite, nanotubes or fullerenes.
A carbon nanotube (CNT) can be visualized as a hollow cylinder formed by rolling graphite sheets. In fact, bonding in CNTs is essentially sp2. However, the circular curvature present in CNTs causes a rehybridization of the three s and the p orbitals typical of the sp2 hybridization. Three s bonds are slightly out of plane, and for compensation the p orbital is more delocalized outside the tube.
This makes carbon nanotubes mechanically stronger, electrically and thermally more conductive, and chemically and biologically more active than graphite.

    2. Growth of CNTs by thermal-CVD

Nowadays, the bottleneck in the carbon nanotechnology is represented by the growth process, in order to achieve worthwhile quantities of a material which should be of high purity and well defined orientation. So far, mainly three techniques have been implemented for the growth of CNTs, but only chemical vapor deposition (CVD) seems able to satisfy the requirements of a high purity material and a reasonable growth rate, compared to arc-discharge and laser ablation methods.
We grow CNT in a CVD reactor (Fig. 1) consisting of a horizontal quartz tube housed in a cylindrical furnace, in which a constant nitrogen gas flow rate is maintained at pressures slightly above the atmospheric, in order to provide the condition of a laminar gas flow. A pyrex flask containing the reagent mixture (composed by a carbon precursor and a catalyst source) is connected, via T joint, to the tube close to the nitrogen inlet. A heater plate is located below the flask.
We use ferrocene as catalyst source, as it is a good precursor for the production of iron nanoparticles, which play the role of catalysts in the formation of nanotubes. As carbon precursor we use camphor, due to the fact that it is non-toxic, commercially available and inexpensive, or cyclohexanol, because it is a good solvent for the ferrocene and allows the constitution of a homogeneous solution. After the evaporation a homogeneous mixture is produced in the gas phase.
furnaceThe process starts with a purge nitrogen flow, aimed to get rid of residual air. The furnace is then heated to the growth temperature (1100°C). Subsequently, the pyrex flask containing the precursors is heated leading to the vaporization of reagents, and the gases are carried into the furnace by the nitrogen gas flow. In the furnace, the high temperature causes the pyrolysis of the gases and the carbon species are deposited on the substrates. Upon cooling to room temperature, a deposit of carbon is found on the inner tube wall and the substrates.

    3. Characterization of the grown material

From electron microscopy images (Figs. 2-4) we can observe that our system allows to grow compact carpets of self-standing, well packed and vertical aligned multi-walled carbon nanotubes (MWNT), which can reach a length of several millimeters without interruptions.
SEM imageThe structure and morphology of carbon nanotubes are characterized by electron microscopy (FE-SEM, HR-TEM) and X-ray Diffraction (XRD). Surface area and porosity analyses are performed by Brunauer-Emmett-Teller method (BET). Samples are also analyzed with micro-Raman spectroscopy in order to obtain information about the structure and the kind of the carbon nanotubes.
The thermal stability is investigated by thermo-gravimetric analysis (TGA).
Electron Spin Resonance (ESR) spectroscopy at room and low temperature (4-30 K) is used to investigate paramagnetic centers and their interaction with the surroundings.
The hydrophobic properties of the CNT carpet are checked by wettability measurements (water contact angle).
The mechanical behavior of nanotubes carpets is tested by measuring compressive strength, rupture modulus (three point system), hardness (shore A durometer), flexibility, tensile stress, resistance to traction (parallel to the surface of carpets).
We are also investigating the purification and functionalization of CNTs: by acid and basic treatments it is possible to produce carboxylic, solfonic and other functional groups, easily detected by FT-IR analysis, XPS and ESR spectroscopies. This allows the chemical adduction of nucleic acids, proteins and other biological molecules, with the aim of CNT application as nano biological sensors.

Contact information
Alberto Tagliaferro
Tel. +39 011 090 7347


  • "Matrices of hydrogen microcombustors"
    Framework: FISR (2005-2008)
    Partners: CRF - Universities of: Torino, Milano, Udine, Napoli, CNR - IENI
  • "Innovative systems for the production of hydrogen from renewable energies"
    Framework: FISR (2005-2008)
    Partners: IPASS - FN SpA - CIRIAF - Environment Park
  • "Innovative materials for hydrogen storage"
    Framework: Regional fundings (2005-2008)
    Partners: University of Torino
  • "Nanostructured carbon based systems for industrial applications"
    Framework: Regional fundings (2005-2008)
    Partners: University of Torino
  • "Functionalization of carbon nanotubes for ambience gas revelation "
    Framework: Regional fundings (2005-2008)
    Partners: University of Torino


  • EDM Group (Electronic Devices & Materials Group), Department of Engineering, Cambridge University, 9, JJ Thompson Ave., Cambridge, CB3 0FA, UK
  • ITC-IRST - Istituto Trentino di Cultura - Ricerca Scientifica e Tecnologica (dal 1 marzo 2007 Fondazione Bruno Kessler ITC), Via Sommarive, 18, 38050 Povo (Trento) Italy
  • Inorganic Chemistry Group, Dipartimento di Chimica IFM, Università di Torino, via Pietro Giuria 7, 10125 Torino, Italy
  • GMP (Gruppo Materiali Polimerici), Dipartimento di Chimica IFM, Università di Torino, via Pietro Giuria 7, 10125 Torino, Italy
  • FN S.p.A. (Nuove Tecnologie e Servizi Avanzati), SS 35bis dei Giovi, km 15, 15062 Bosco Marengo (AL), Italy


  • [download pdf] "Growth of vertically aligned carbon nanotubes by CVD by evaporation of carbon precursors",
    S. Musso, G. Fanchini, A. Tagliaferro,
    Diamond & Related Materials 14 (2005) 784- 789

  • [download pdf] "Thermal CVD Growth of Carbon Nanotubes Thick Layers",
    Samuele Porro, Simone Musso, Mauro Giorcelli and Alberto Tagliaferro,
    Proceeding CIMTEC Conference 2006 - Advances in Science and Technology 48 (2006) 37-43

  • [download pdf] "Thermal CVD System designed for Growth of Carbon Nanotubes",
    Samuele Porro, Simone Musso, Massimo Rovere, Mauro Giorcelli, Angelica Chiodoni, Alberto Tagliaferro
    Proceedings of ESDA2006: 8th Biennial ASME Conference on Engineering Systems Design and Analysis - ESDA2006-95721

  • [download pdf] "Low Temperature Electron Spin Resonance Investigation of Ultrananocrystalline Diamond Films as a Function of Nitrogen Content",
    M.Rovere, S.Porro, S.Musso, A.Shames, O.Williams, P.Bruno, A.Tagliaferro, D.M.Gruen Proceeding of ICNDST-ADC 2006 - Diamond and Related Materials 15 (2006) 1913-1916

  • [download pdf] "Study of CNTs and nanographite grown by thermal CVD using different precursors",
    S. Porro, S. Musso, M. Giorcelli and A. Tagliaferro S. H. Dalal, K. B.K. Teo, D. A. Jefferson and W. I. Milne
    Proceeding ICANS 2006 - Journal of Non-Crystalline Solids 352 (2006) 1310-1313

  • [download pdf] "Low temperature electron spin resonance investigation on SWNTs after hydrogen treatment" ,
    S. Musso, S. Porro, M. Rovere, A. Tagliaferro, E. Laurenti, M. Mann, K.B.K. Teo and W.I. Milne,
    Proceedings of Diamond and related materials 2005, Toulouse (France), 11-16 September 2005 - in press

  • [download pdf] "Purification of carbon nanotubes grown by thermal-CVD",
    S. Porro, S. Musso, M. Vinante, L. Vanzetti, M. Anderle, F. Trotta, A. Tagliaferro
    Proceeding E-MRS 2006 - Physica E 37 (2007) 58-61

  • [download pdf] "Optimization of a thermal-CVD system for carbon nanotubes growth",
    S. Porro, S. Musso, M. Giorcelli, A. Chiodoni, A. Tagliaferro
    Proceeding E-MRS 2006 - Physica E 37 (2007) 16-20

  • [download pdf] "Growth and characterization of Carbon nanotubes as hydrogen storage system",
    Simone Musso, Samuele Porro, Mauro Giorcelli
    Proceeding HYSYDAYS 2005, 1st World Congress of Young Scientist on Hydrogen Energy Systems (18th-20th May 2005 Turin, Italy)

  • [download pdf] "Physical and mechanical properties of thick self standing layers of multiwall carbon nanotubes",
    S. Musso, S. Porro, M. Rovere, A. Chiodoni, and A. Tagliaferro
    Proceeding DIAMOND 2006 - Diamond and Related Materials 16 (2007) 1174-1178

  • [download pdf] "Modification of MWNTs obtained by thermal-CVD",
    S. Musso, S. Porro, M. Vinante, L. Vanzetti, R. Ploeger, M. Giorcelli, B. Possetti, F. Trotta, C. Pederzolli, A. Tagliaferro
    Proceeding DIAMOND 2006 - Diamond and Related Materials 16 (2007) 1183-1187

  • [download pdf] "Defects localization and nature in bulk and disperse ultrananocrystalline diamond",
    A. I. Shames, A. M. Panich, S. Porro, M. Rovere, S. Musso, A. Tagliaferro, M. V. Baidakova, V. Yu. Osipov, A.Ya.Vul, T. Enoki, M. Takahashi, E. Osawa, O. A. Williams, P. Bruno, D. M. Gruen
    Proceeding SMAC 2006 Creta - DRM – in press

  • [download pdf] "Macroscopic growth of carbon nanotube mats and their mechanical properties",
    Simone Musso, Samuele Porro, Mauro Giorcelli, Angelica Chiodoni, Carlo Ricciardi, Alberto Tagliaferro
    Carbon / Letters to the Editor, 45 (2007) 1133-1136

  • "Improving macroscopic physical and mechanical properties of thick layers of aligned multiwall carbon nanotubes by annealing treatment",
    S. Musso, M. Giorcelli, M. Pavese, S. Bianco, M. Rovere, A. Tagliaferro
    Proceeding NDNC 2007 - Diamond and Related Materials

  • "Fluid dynamic analysis of gas flow in a thermal-CVD system designed for growth of carbon nanotubes",
    Simone Musso, Samuele Porro, Massimo Rovere, Mauro Giorcelli, Alberto Tagliaferro
    Journal of Crystal Growth - submitted

  • "Biocompatibility of carbon-based materials",
    M.Vinante, S. Forti, C. Pederzolli, M.Giorcelli, S. Musso, A. Tagliaferro, et al.
    Proceeding Nanosmat 2007 - submitted

  • "Gas chromatography study of reagent degradation during CVD carbon nanotube growth",
    Simone Musso, Marco Zanetti, Mauro Giorcelli, Alberto Tagliaferro, Luigi Costa
    Proceeding Nanosmat 2007 - Journal of Nanoscience and Nanotechnology - submitted

  • "Preparation of polymer-based composite with magnetic and electronic anisotropy by oriented carbon nanotube dispersion",
    Alessandro Chiolerio, Simone Musso, Marco Sangermano, Mauro Giorcelli, Stefano Bianco, Marco Coïsson, Aldo Priola, Paolo Allia, Alberto Tagliaferro
    Proceeding DIAMOND 2007 - Diamond and Related Materials - submitted

  • "Thermal CVD growth of nanocrystalline graphite and study of biological properties",
    Simone Musso, Samuele Porro, M.Vinante, S.Forti, C.Pederzolli, S. H. Dalal, K. B.K. Teo, D. A. Jefferson, W. I. Milne, Alberto Tagliaferro Proceeding DIAMOND 2007 - Diamond and Related Materials - submitted