Abstract :
The surface modification of multi-walled carbon nanotubes (MWCNTs) by O2 plasma was carried out in this study. In order to achieve a
relatively homogeneous treatment of MWCNTs powder, a rotating barrel fixed between the two discharge electrodes was used. The effect of
plasma treatment parameters, such as power, time, and positions of samples (inside and outside the barrel), on the morphology and structure of
MWCNTs surface was systematically analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results
showed that the direct discharge (outside the barrel) could result in not only a quick grafting of polar functional groups but also an easy damage of
MWCNTs after longer time, particularly under intensive power. It was found that the surface of MWCNTs powder might be changed in three
steps—expansion (loosed structure formed), peel off and oxidization with increasing of treatment time during the irradiation. In this way, a
complete purification of MWCNTs powder could be finished within 30 min via plasma treatment. Our work suggested that plasma treatment could
be a simple and nonpolluting method for a large scale purification of MWCNTs.
