Activation energy and optical energy gaps of ion-irradiated high-density polyethylene

Ion implantation of hydrogen and helium ions into high-density polyethylene (HDPE) films were performed. The influence of ion implantation on the optical absorption and the thermal properties of HDPE were investigated. The variation of the specific heat at constant pressure Cp with ion fluence gives an estimate of the activation energy of ordering which was found to be dependent on the fluence and the type of ion implanted in the polymer. The optical absorption spectra in the wavelength range 200 to 900 nm at different implantation ion fluence has been measured. The absorption coefficient, the energy gaps (Eopt) and (ΔE) were calculated and found to depend on the ion implantation fluence. The different effect of H+ and He+ ion-implantations on the morphological changes of the polymer structure were clarified. (author)