Oxygen functionalization of multiwall carbon nanotubes by Ar/H_2O plasma treatment

摘要

To increase the applicability of multiwall carbon nanotubes (MWCNTs), oxygen-containing functional groups were introduced on the surfaces of MWCNTs by using microwave-excited Ar/H_2O surface-wave plasma. X-ray photoelectron spectroscopy and Raman spectroscopy were used to determine dependencies of Ar/H_2O gas partial pressure, treatment time and microwave power. The oxygen functionalization of MWCNTs by plasma can be achieved very rapidly, about 10 min. The C-0 and 0-G=0 fractions firstly increase and then decrease with increasing Ar partial pressure. The C-0 and 0-C=0 fractions increase with increasing microwave power from 400 W to 700 W. A slight increase of the R (I_D/I_G ratio) value for the treated MWCNTs indicated disordering in the surface microstructure of MWCNTs coincident with the introduction of surface oxygen. The oxygen-containing groups introduced on the surfaces of MWCNTs by plasma treatment are hydrophilic. The dispersion of plasma treated MWCNTs is therefore improved.