Abstract Submitted to the NANOTUBE'02 Workshop:

A simple theoretical scheme is presented in order to interpret the growth mechanism in carbon nanotubes obtained by chemical vapour deposition which are catalysed by the presence of transition metal nanoparticles. Within the frame of this model it is put forward as the assembling of carbon nanotubes arises from a capillary effect. In fact, it is suggested as the growth is prompted by the interface tension force which originates by the interaction of those atoms at the surface of the transition metal nanoparticle catalyst with the carbon atoms or carbon dimer molecules present in the formed carbon gas. Moreover we show as the growth of a carbon molecule occurs in a diffusive gas regime and determines a viscous force opposing the elongation of the molecule. The composing effect of these forces can be directly gathered in a general equation which allows us to easily interpret the experimental data. By means of this equation the tip-growth and the end-growth mechanisms are investigated. An interpretation of the catalyst action considering the action of d-atomic orbitals is also given.