Surface Modification of Vapor-grown Carbon Nanofibers in Radio Frequency Plasma

Vapor-grown carbon nanofibers (VGCNFs) were treated in radio frequency (RF) plasma to activate their surface and thus to improve the compatibility with the matrix in polymer composites. The surface of VGCNFs was modified in atmospheres containing different ratios of O2 and Ar. Fourier transform infrared spectroscopy and thermogravimetric measurement shows that when the O2 content in mixture gases was 5%, C-O and O-H functional groups were produced abundantly in the surface of the VGCNFs. When O2 content increased to 8%, most of the surface of carbon fibers was severely oxidized, resulting in defects in structures of the inner layers of VGCNFs.