A study of structural and spectral properties of ion-beam modified polyethylene terephthalate membrane

In this study, we investigated a modification of the structure of polyethylene terephthalate (PET) membrane exposed to 100 keV N5+ ions with fluences varying from 10(14) to 10(16) ions/cm(2). The changes in the properties of the ion-beam modified samples of PET membrane were analyzed by Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) and dielectric spectroscopies. FTIR spectra showed a change in the intensity of the typical bands after the irradiation of the polymers. The results of the optical measurements showed that the increase in the ion irradiation fluence induced a decrease in the transmittance of the PET membrane. The estimated value of the energy band gap decreased with the increase of the fluence. A significant decrease of the energy band gap was observed for the ion beam fluence of 10(16) ions/cm(2). The dielectric measurements performed in a wide frequency band in the range from 20 Hz to 10 MHz and temperature range from 120 K to 400 K revealed that ion beam treatment with a fluence of 10(16) ions/cm(2) changed the characteristic temperature dependence of the dielectric loss tan delta (T).