Mechanics of Nanotubes Filled With C60, C36 and C20

Abstract

The mechanical properties of single-walled nanotubes (SWNTs) filled with small fullerenes (C20, C36 and C60) were investigated using molecular dynamics (MD) simulation. The interaction between carbon atoms was described by a combination of the many-body Brenner potential with a two-body pair potential. We found that below the critical value of the strain, the stress of SWNT increases linearly with the strain and the Young's modulus of certain SWNT with different filling densities is almost the same for small strain. It was also observed that the buckling force, which corresponds to the critical strain, becomes higher as the filling density of SWNT is increased in general. However, in the case of SWNT of larger radius filled with smaller fullerenes, the dependence of the buckling force on the filling density is expected to be different, which was attributive to the long-distance attractive interaction between atoms of fullerene and those of SWNT.

One-Dimensional Crystals inside Single-Walled Carbon Nanotubes: Growth, Structure and Electronic Properties

“…In fact, the oxidation involves both the ends and the walls of carbo n nanotubes. F or example, treatment of SWNTs with an acid was shown to result in the lateral defects formation (one defect per each 5 nm of the nanotube) (Zhang et al, 2003). Unlike that of multi-walled nanotubes, partial oxidation of single-walled nanotubes leads to formation of "hole" defects, through which substances may penetrate into the tubes both through their ends and walls.…”

“…For such treatment, the opening of nanotubes is practically complete. In this process the sample loses approximately 40% of its mass (Zhang et al, 2003). …”

“…The excess of the encapsulated compound that remains at the SWNT's outer surface can be potentially removed by washing the sample or heating it under dynamic vacuum conditions. The retraction of liquids into single-walled nanotubes takes place only if a number of conditions is met (Zhang et al, 2003). First, carbon nanotubes must be opened at least from one end.…”

“…RuCl 3 , AgNO 3 , and Fe(NO 3 ) 2 ) are most often employed to encapsulate the SWNTs by the ex situ approach from the liquid phase (Chen et al, 1997;Monthioux, 2002;Monthioux et al, 2006) (Fig. 3) Another popular solvent is nitric acid, which is used due to its low surface tension (43 mN·m -1 ), allows avoiding a separate opening procedure (Zhang et al, 2003). As a rule, the second step upon the SWNTs' treatment with a solution is thermal treatment or hydrogenation in an H 2 flow at 150-450°C for several hours; this leads to the formation of metal or oxide nanoparticles inside the SWNTs.…”

“…metals, oxides, chlorides, fullerenes and endofullerenes). However, this method has a number of limitations and disadvantages (Zhang et al, 2003). First, due to the procedure's nature the SWNT channels may be contaminated with the solvent, the products of its interaction with the nanotube walls and/or the encapsulated compound.…”