Ambika Negi

Effects of Li and Au ion beams irradiation on Makrofol-KG

The Makrofol-KG polycarbonate (M-KG PC) films were irradiated with 45 MeV Li+3 and 150 MeV Au+9 ion beams at various fluences ranging from 1010 to 1012 ions/cm2. Structural, chemical, and optical and surface properties were investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV–visible, and atomic force microscopy (AFM), respectviely, as a function of ion fluences. UV–visible spectra exhibit a shift toward the higher wavelength regime after irradiation. This shift clearly reflects decrease in the optical band gap after irradiation. The FTIR spectra show a decrease in intensity of the typical bands. The XRD pattern of M-KG PC shows the decreasing intensity of peak with increase in ions fluence, which reflects loss of crystallinity of the films due to ion beam irradiation. AFM shows that the surface becomes rougher after irridation. The magnitude of the effect of irradiation is larger in the case of 150 MeV Au+9 rather than 45 MeV Li+3 ions due to high electronic energy loss of the Au ions in M-KG PC. The results can be discussed on the basis of linear energy transfer of the irradiated ions.

Modifications induced by O+8 ion beam to Lexan polycarbonate

High-energy ion beam irradiation of polymer is an effective technique to enhance the optical, structural and mechanical properties. Lexan polycarbonate films were irradiated by oxygen ions (energy 100 MeV, charge state O+8) with fluence varying from 3×1010 to 3×1012 ions/cm2. Ion beam-induced optical and structural modifications were studied by ultraviolet–visible (UV–Vis), X-ray diffractometer and Fourier Transform Infrared (FTIR) spectroscopy. It is observed that optical absorption increases with increasing fluencies. The absorption edge was also found to shift from the UV region to the visible region. Value of band gap shows a decreasing trend with increasing ion fluences. The correlation between the optical band gap and number of carbon atoms inside the carbon clusters embedded in the network of Lexan has been discussed. X-ray Diffraction (XRD) analyses show the significant change in crystallinity with fluences. FTIR spectra show that the intensity of the absorption bands of Lexan polymer decreases after ion beam irradiation.

The role of electronic energy loss in PET polymer

Semi-crystalline films (100 μ m) of the non-conducting polymer polyethylene terephthalate (PET) were exposed to swift heavy ions of 45 MeV Li3+ (S e=7.29E+00 eV/Å) and 120 MeV Au9+ (S e=1.157E+03 eV/Å) at ion fluence ranging from 1010 to 1012 ions/cm2. The chemical and structural properties were investigated using Fourier transform infra-red (FTIR) spectroscopy and X-ray diffraction techniques. The optical studies were carried out by UV–visible spectroscopy. It was noticed that the value of the band gap decreases with increasing fluence and depends on energy loss during interaction. A significant loss of crystallinity and change in the size of the particle are observed in irradiated PET. FTIR studies of the samples show the chemical changes after irradiation. The atomic force microscopy observation revealed that the surface morphology changes after irradiation.