Preparation of polymer films by laser ablation of polyacrylonitrile: significant dependence on ablation wavelengths

Preparation of reorganized polymer films has been made by deposition of laser-ablated fragments of polyacrylonitrile (PAN), using XeCl (308 nm), KrF (248 nm), and ArF (193 nm) excimer lasers. Morphologies, chemical compositions and molecular structures of reorganized films were probed by scanning electron microscopy (SEM), IR spectroscopy and X-ray photoelectron spectroscopy (XPS). Significant dependence on ablation wavelengths was observed for structural variation as compared to the original PAN: the original structure was essentially preserved by ablation at 308 nm, while extensive cyclization of the nitrile group to yield condensed-ring formation was observed by ablation at 248 nm. Ablation at 193 nm caused elimination of the nitrile group.