An XPS Study of Vacuum Ultraviolet Photo-oxidation of Carbon Nanotubes.
M. R. Rasmussen1; D. D. Allred1
1. Physics & Astronomy, Brigham Young, Provo, UT, USA.
of carbon nanotubes (CNTs) occurred with exposure to 172 nm vacuum
ultraviolet (VUV) light from a xenon excimer lamp, in air. X-ray
photoelectron spectroscopy (XPS) showed that after 15 min. of
oxidation, nearly 45% of the carbon atoms were functionalized into
ether, carbonyl, and carboxyl groups (identified by curve-fitting of
the C 1s peak). In spite of the high level of oxidation, the CNTs did
not deteriorate; their structure was maintained when viewed by scanning
electron microscopy (SEM). Functionalizing CNTs is faster with VUV
exposure than with UV/ozone oxidation due to higher energy photons (7.2
eV) affecting photo-oxidation and creating atomic oxygen; VUV exposure
is also advantageous over acidic oxidation because it creates no liquid