Ion beam modification of PES, PS and PVC polymers (original) (raw)
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7 Abstract 8 Physical and chemical changes induced by 70 MeV carbon ions 12 C 5 have been investigated in bulk polyvinylidene 9¯uoride (PVDF) polymer. The induced changes have been studied with respect to their optical, chemical and structural 10 response using UV±visible, FTIR and XRD techniques. The ion¯uences ranging from 2:5 Â 10 11 to 9 Â 10 13 ions cm À2 11 have been used to study the irradiation eects. It has been observed that at the¯uence of 9 Â 10 13 ions cm À2 the PVDF 12 sample became brittle and practically it was not possible to handle it for any further measurements. The recorded UV± 13 visible spectra show that the optical absorption increases with increasing¯uence, indicating maximum absorption at 14 200 nm. An interesting feature of UV±visible spectra is that dips change into peaks and vice versa with increase of 15¯uence. In the FTIR spectra, development of new peaks at 1714 and 3692 cm À1 along with disappearance of peaks at 16 2363 and 3025 cm À1 and shifting of peak at 2984±2974 cm À1 have been observed due to high energy irradiation, in-17 dicating the chemical changes induced by 12 C 5 . The diraction pattern of PVDF indicates that this polymer is semi-18 crystalline in nature; a large decrease in the diraction intensity indicates decrease in crystallinity. Increase in crystallite 19 size has also been observed due to heavy ion irradiation. Ó
Ion irradiation induced chemical changes of polymers used for optical applications
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1997
Polymers are a class of materials widely used in different fields of applications. In the field of optical telecommunication, polymers are discussed as a new class of materials for the fabrication of passive optical devices. Ion irradiation is a promising method to generate structures with a modified index of refraction, which is necessary for the guidance of light with different wavelengths in an optical device. The behaviour of different polymers which fulfil the requirements of high transparency has been studied during and after ion irradiation. Mass spectroscopy measurements of the reaction products outgassing during ion irradiation were performed as well as infrared (IR) measurements after irradiation. Ion induced chemical changes will be discussed in relation to modified macroscopic properties such as the index of refraction.
Infrared analysis of ion beam irradiated polymers
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2009
Irradiation with heavy ions can produce several modifications in the chain structure of polymers. These modifications can be related to scissioning and cross-linking of chemical bonds, which depend on the ion fluence and the density of energy deposited in the material. Stacked thin film Makrofol-KG Ò samples were irradiated with 350 MeV Au 26+ ions and FTIR absorption spectroscopy was used to determine the bond changes in the samples. Data on the absorption bands as a function of the fluence indicated a higher probability for simple-bonds scissioning than for double-bonds scissioning and no dependence on the number of double bonds breaking with ion fluence. Since sample irradiation was done in a non-trackoverlapping regime, a novel process for double bonds formation is suggested: the excitation of a site in the material by only one incident ion followed by a double bond formation during the de-excitation process.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1991
The keV-MeV ion irradiation of polymers produces deep changes in their physical and chemical properties associated with the breaking and rearrangement of original bonds. The modification of chain structure occurs within a well defined ion fluence range which depends on the ion linear energy transfer as well as on the target parameters. At low ion fluences (≈1014 ions/cm2) crosslinks between chains and chain-scissions are detected with a chemical yield in the range 0.05–0.3, depending on the ion mass. With increasing ion fluence (1015 ions/cm 2) the original polymer structure is heavily modified and the irradiated films exhibit properties close to those of hydrogenated amorphous carbon. At very high fluences (≈1016 ions/cm 2) graphitization of the material occurs.
Study of the effects of MeV Ions on PS and PES
MRS Proceedings, 1997
ABSTRACTThe electronic and nuclear stopping effects produced by MeV ion bombardment in polyethylene (PE) and polyvinylidene chloride (PVDC) have been previously studied and reported. We have subsequently selected two other insulators: polystyrene (PS) and polyethersulfone (PES) which contains sulfur as a crosslinking agent, and irradiated them with MeV alpha particles. The electronic and nuclear effects of the incident ions were separated by stacking thin films of the polymers. A layered system was selected such that the first layers experienced most of the effects of the electronic energy deposited and the last layers received most of the effects of the nuclear stopping. The changes in the chemical structure were measured by residual gas analysis (RGA), Raman microprobe analysis, RBS and FTIR. The post-irradiation characterization resolved the effects of the stopping powers on the PS and PES and the results were compared with those from PE and PVDC.
Structural modification of polymer films by ion irradiation
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1992
The atomic and electronic structure of polymer films undergoes deep modifications during high energy (keV-MeV) ion irradiation, from molecular solid to amorphous material. At low energy density (1022–1024) typical effects include chain scissions, crosslinks, molecular emission and double bonds formation. In hydrocarbon polymer (polystyrene, polyethylene) the main effect of irradiation is the formation of new bonds as detected by molecular weight distribution, solubility and optical measurements. Moreover the concentration of trigonal carbon (sp2) in the polymer changes with ion fluence (1011–1014) and stabilizes to a value of 20% independently on the initial chemical structure of the irradiated sample. Photoemission spectroscopy shows an evolution of valence band states from localized to extended states. At high energy density (1024–1026) the irradiated polymer continues to evolve showing spectroscopic characteristics close to those of hydrogenated amorphous carbon. Trigonal carbon concentration changes with ion fluence (1014–1016) reaching the steady state value of 60% and the hydrogen concentration decreases to 20%. Moreover the values of the optical gap (2.5–0.5 eV) suggest the presence of medium range order in the obtained hydrogenated amorphous carbon. These values are consistent with the formation of graphitic clusters, whose size goes from 5 Å to 20 Å by changing the ion fluence (or energy density).
Electrical and Optical Properties of O6þ Ion Beam–Irradiated Polymers
Variations in dielectric, optical, and structural properties of Lexan and Kapton-H irradiated to 80MeV O6þ ion beam were analyzed at different fluences ranging from 1011 to 1013 ions=cm2 with a scanned beam current of 1 pnA. The structural modifications were characterized with the help of FT-IR and UV-vis spectroscopies. The electrical properties were investigated through capacitance and dielectric loss variations in ion-irradiated and pristine polymers at different frequencies. UV-vis absorption analysis indicates a decrease in the band gap energy in the two polymers. However, the decrease is much more prominent in Lexan (30%) than in Kapton-H (2.5%). The dielectric constant does not show appreciable variations after ion irradiation; however, a small increase has been noticed. An overall increase in the intensities of some typical bonds and stretching was observed in the FT-IR spectra of the pristine and ion-irradiated polymers.
INTERNATIONAL CONFERENCE ON SCIENCE AND APPLIED SCIENCE (ICSAS) 2019, 2019
Application of positron annihilation spectroscopy using a variable-energy slow positron beam (VESPB) as a key experimental tool to understand ion-induced processes and defect structures in a number of polymer composite materials important for a practical use is demonstrated. The results concerning 40 keV B + implanted polymethylmethacrylate (B:PMMA) and 30 keV Ag + implanted PMMA (Ag:PMMA), and organic-inorganic ureasil composite (Ag:ureasil) are discussed. Utilized VESPB techniques allow to confirm carbonization of ion-irradiated B:PMMA, formation of carbon-shell Ag-core nanoparticles in Ag:PMMA and evolution in size of Ag nanoparticles in Ag:ureasil, which was revealed by means of UV-Vis absorption and Raman spectroscopy measurements.