EFFECT OF ACCELERATED AGING BY ULTRAVIOLET RADIATION ON MULTI-WALLED CARBON NANOTUBES
Justin M. Gorham, R. David Holbrook, Tinh Nguyen, D. Howard Fairbrother
Surface and Microanalysis Science Division
The effect of ultraviolet (UV) aging on multi-walled carbon nanotubes (CNTs) has been investigated. To accelerate the rate of UV exposure, two-dimensional thin films of CNTs formed through filtration were placed in the SPHERE. The SPHERE supplies high intensity, UV radiation uniformly over a sample under constant conditions in order to simulate years of solar exposure in a matter of weeks. X-ray photoelectron spectroscopy (XPS) studies focused on the change in the CNT surface chemistry with increasing UV exposure. XPS based methods for determining the extent of oxidation, elemental distribution and functional group concentrations will be presented. Through depth profile measurements, Auger electron spectroscopy (AES) studies will determine the extent that oxidation occurs in the bulk of the CNT film. Using a combination of XPS and AES, the effect of UV radiation and other reactive species on the residual, catalytic elements (iron) in the CNT will also be explored.