Spatially resolved electronic modifications of a thin poly(acrylonitrile) film induced by synchrotron radiation white beam

Abstract

NEXAFS experiments at the C and N K-edges, Fourier transform infrared spectroscopy, and photoemission measurements at variable excitation energy have been used to characterize the electronic and structural modifications occurring in thin poly(acrylonitrile) (PAN) films when they are irradiated by a synchrotron radiation white beam. Upon irradiation, the nitrile groups are rapidly removed from the film and the H content is substantially reduced. The final chemical composition of the layer is similar to that of graphite, with highly delocalized electrons located just below the Fermi level. The mechanism which leads to this structure is different from that observed when PAN is annealed. The extent of transformation is controlled by the exposure time to the synchrotron white beam and is spatially localized to the irradiated area. New applications of the synchrotron white beam in the synthesis of materials may be envisioned. 35 refs., 5 figs., 2 tabs.