Synthesis of Carbon Nanotubes by Arc Discharge in CF₄ Gas Atmosphere

Abstract

Carbon nanotubes were synthesized by arc discharge in a CF4 gas atmosphere involving fluorine atoms, which are able to terminate carbon bonding, while no fullerenes were synthesized in a CF4 gas atmosphere. The morphology of these nanotubes was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Based on these results, the synthesized conditions in CF4 gas were compared with those in other gases, i.e., in CH4, H2, He and Ar gases. In addition, electron spin resonance (ESR) measurements were performed in order to obtain information about the electronic properties of these nanotubes.

Study of electroactive shape memory polyurethane–carbon nanotube hybrids

“…Hence, MWCNTs may be metallic and it is also possible that they may be semiconducting. 29,30 In addition, the inner walls of MWCNTs do not contribute significantly to the mechanical properties of the materials, making SWCNTs more attractive to researchers. Therefore, single-walled carbon nanotube is an excellent candidate for developing polymer conductive composites.…”

Morphology and electronic properties of carbon nanotubes synthesized by arc discharge in CF4gas

“…The ESR spectra are similar among the groups and consist of two components: a broader component located at a lower magnetic field and a narrower component located at a higher magnetic field. The broader component was attributed to the nanotubes and the narrower component to the carbon nanoparticle, micrometer flakes and/or amorphous carbon, as the inner part of the deposit contains many carbon nanotubes [8]. These assignments of the ESR spectra were confirmed in the annealed sample, for which the spectrum showed a decrease in the intensity ratio of the broader component to the narrower component.…”

“…We recently reported the synthesis, morphology and electronic properties of carbon nanotubes in a CF 4 gas atmosphere by arc discharge [8]. The morphology plays an important role in the electronic properties of carbon nanotubes as suggested by theoretical studies which have shown that the electronic properties of a single nanotube depend on structural properties such as its helicity [9,10].…”

Methods for preparation of carbon nanotubes

“…Yokomichi et al 97 have attempted to prepare NT in a CF 4 medium. It has been assumed that the F atoms formed upon decomposition of CF 4 would attach to the dangling bonds and prevent them from closing, thus influencing the process of NT formation.…”

“…The researchers cited 97 studied the influence of the main parameters of the process (medium, gas pressure and current) on the yield of NT and polyhedral particles and on the length of NT and compared their data with those reported in other publications; the results were summarised in a table (Table 2). In particular, it follows from this table that the processes occurring in an atmosphere of CF 4 and CH 4 are fairly similar.…”