Amino group introduction onto multiwall carbon nanotubes by NH3/Ar plasma treatment

Multiwall carbon nanotubes (MWCNTs) were modified by using a microwave-excited NH3/Ar surface-wave plasma. Changes in the atom composition and structural properties of the modified MWCNTs were studied as a function of gas flow rate, treatment time, microwave power, and bias voltage by using X-ray photoelectron spectroscopy and Raman spectroscopy. The results suggest that nitrogen-containing groups were introduced on the surfaces of the MWCNTs and that the concentration of primary amino groups was affected by gas flow rate, microwave power, and bias voltage. The contact angle of water on the modified MWCNTs decreased and the hydrophilicity of the modified MWCNTs was improved. The surface morphology and structure of the MWCNTs were not destroyed by the plasma treatment. (C) 2009 Elsevier Ltd. All rights reserved.