SURFACE CHARACTERIZATION OF CARBON-FIBERS USING ANGLE-RESOLVED XPS AND ISS

Angle-resolved X-ray photoelectron spectroscopy (ARXPS) and ion-scatte ring spectroscopy (ISS) are utilized to investigate the surface compos ition of BASF type II carbon fibers as a function of progressive expos ures to aqueous nitric acid. To the authors' knowledge this is the fir st such study of carbon fibers to incorporate both of these surface an alytical techniques. Overall, the ARXPS and TSS spectra are shown to b e highly synergistic and quite consistent with one another. The data i ndicate that the surface composition of the as-received fibers is hete rogeneous and undergoes significant changes upon nitric acid exposure. The net effect of the nitric acid surface treatments appears to be th e systematic and preferential formation of carbonyl and carboxyl group s, and the establishment of a more uniform surface composition as a fu nction of depth. It is expected that these data will contribute toward a better understanding of the interphase in carbon fiber composites.