J. M. S. Rana

A comparative study of the effect of O+7ion beam on polypyrrole and CR-39 (DOP) polymers

Polypyrrole thin films doped with para-toluene sulphonic acid were prepared by the electrochemical process. High-energy ion beam irradiation of the polymers is an effective technique to enhance the electrical conductivity, structural property and mechanical properties. So polypyrrole and allyl diglycol carbonate (CR-39 (DOP)) films were irradiated by oxygen ions (energy 100MeV, charge state O +7 ) with fluence varying from 1 × 10 10 to 1 × 10 13 ionscm −2 . The effects of swift heavy ions (SHI) on the structural, optical and surface properties of polypyrrole (Ppy) and CR-39 (DOP) polymers were studied in this work using x-ray diffraction (XRD), UV‐visible spectroscopy and scanning electron microscopy (SEM). XRD patterns of the pristine and irradiated polymer show that the crystallinity improved after the irradiation with SHI. At the low fluence, crystallinity was found to increase but at high fluence, it decreases which could be attributed to cross-linking and degradation mechanism. The UV‐visible spectra show a shift in the absorbance edge towards higher wavelength, which can be correlated with the transition involved in the polymer and variation in the band gap using Tauc’s expression. The band gap of polypyrrole was found to decrease from 3.4 to 3.0eV after irradiation. CR-39 (DOP), however, showed a very large change in the band gap from 4.8 to 3.4eV. The SEM study shows a systematic change in the surface morphology of the polymers with increasing ion fluence. (Some figures in this article are in colour only in the electronic version)

Effects of swift heavy ions irradiation on polypyrrole thin films

Abstract Conducting polypyrrole (PPY) polymer thin films, prepared by the electrochemical process, were irradiated with 50 MeV Li3+ and 90 MeV C6+ ions at different fluences, ranging from 1011 to 1014 ions cm−2. The structural and electrical properties of the swift heavy ions (SHI) irradiated films were analyzed using X-ray diffraction (XRD), Scanning electron microscope (SEM), and conductivity measurement methods. XRD analysis of SHI irradiated PPY films shows that the crystallinity of the PPY films increases with increasing fluences of lithium ions, but tends to become amorphous at higher fluence. Carbon ions irradiations lead to polymer destruction and simultaneous amorphization even at low fluence. The SEM studies of irradiated PPY films show systematic change in their surface morphologies. The surface was smoother at lower fluence but craters were observed at higher fluence. The surface conductivity of films increases with increasing fluence of lithium ions, which also turn to the virgin film conductivity at higher fluence. It was found that carbon ions do not much affect the surface conductivity of PPY.

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.