Ion Beam-Induced Modifications in the Optical and Structural Characteristics of Lexan Polycarbonate

Lexan polycarbonate samples have been irradiated with lithium, Li+3 (50 MeV) and nickel, Ni+9 (120 MeV) ion beams at the fluence ranging from 3 x 1010 to 3 x 1012 ions/cm2. The effects of ion beam irradiation on Lexan polycarbonate were investigated using x-ray diffraction (XRD), ultraviolet (UV)-visible, and atomic force microscopy (AFM). The UV-visible spectra of ion beam- irradiated films reveal that the optical band gap of polycarbonate decreases with increasing ion beam fluence. The optical band gap shrinks more after irradiation by nickel ion beam because it loses more electronic energy than lithium-ion beams. The number of carbon atoms in carbon clusters incorporated in the Lexan polycarbonate is studied in relation to the optical band gap. The XRD analysis reveals that the intensity of the main peak decreases with increasing ion fluence, indicating the amorphization of Lexan polycarbonate. AFM analysis indicates systematic changes in the surface morphology of polymer films as beam intensity increases.