Evolution of the absorption edge of PET films irradiated with Kr ions after thermal annealing and ageing

This paper presents the results of a study of polyethylene terephthalate (PET) films irradiated with Ar and Kr ions at both normal orientation and an angle of 40° to the normal. Normal irradiation was performed using Ar8+ and Kr15+ ions with an energy of 1.75 MeV/au and fluences in the range (2–500) × 1010 cm−2 for Ar8+ ions and (1.6 − 6.5) × 1010 cm−2 for Kr15+ ions. Kr ions with an energy of 1.2 MeV/au and charges of 13+, 14+, and 15+ were used for angled irradiation. For each Kr ion charge value, three fluence values were used: 5 × 1010, 1 × 1011, and 2.5 × 1011 cm−2. It is well known that irradiation of PET films by swift heavy ions results in a red shift of the UV-vis transmission spectra absorption edge. The experimental transmission spectra exhibit well-defined interference fringes, which obscure the underlying transmission response. Using an existing technique to obtain interference-free transmission curves Tα(λ) for both pristine and irradiated PET film samples, we found that S, the total radiation-induced absorption of light by the PET film, is proportional to the logarithm of the fluence F. In addition to this dependence on the irradiating fluence, we also found that the charge of the irradiating ion has a significant influence on the position of the absorption edge in the UV-vis spectra. This provides experimentally independent evidence to confirm our previous results showing that ion charge has an effect on the post-irradiation state of PET films. We present a physical interpretation of the observed absorption edge red shift in irradiated PET films as being due to the growth of extended conjugated systems via the formation of intermolecular helical structures. Our investigations into the stability of irradiation-induced effects in PET films show that comparison of UV-vis transmission spectra before and after annealing can provide information about the structure of deep traps in PET.

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Soft X-Ray Absorption Spectra of Polyethyleneterephtalate (PET) Films ~ Mass Absorption Coefficient of Oxygen at the O K-Absorption Edge ~

Vacuum and Surface Science ◽

10.1380/vss.63.470 ◽

2020 ◽

Vol 63 (9) ◽

pp. 470-475

Author(s):

Yasuji MURAMATSU ◽

Yuya MATSUMOTO ◽

Eric M. GULLIKSON

Keyword(s):

Absorption Coefficient ◽

Absorption Spectra ◽

Absorption Edge ◽

Mass Absorption Coefficient ◽

X Ray ◽

Mass Absorption ◽

X Ray Absorption ◽

Pet Films

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Annealing Of Radiation Damage in Tungsten

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069053 ◽

1970 ◽

Vol 28 ◽

pp. 412-413

Author(s):

Robert C. Rau ◽

John Moteff

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Radiation Damage ◽

Thermal Annealing ◽

Neutron Fluence ◽

Dislocation Loops ◽

Defect Clusters ◽

Polycrystalline Tungsten ◽

Transmission Electron ◽

Radiation Induced

Transmission electron microscopy has been used to study the thermal annealing of radiation induced defect clusters in polycrystalline tungsten. Specimens were taken from cylindrical tensile bars which had been irradiated to a fast (E > 1 MeV) neutron fluence of 4.2 × 1019 n/cm2 at 70°C, annealed for one hour at various temperatures in argon, and tensile tested at 240°C in helium. Foils from both the unstressed button heads and the reduced areas near the fracture were examined.Figure 1 shows typical microstructures in button head foils. In the unannealed condition, Fig. 1(a), a dispersion of fine dot clusters was present. Annealing at 435°C, Fig. 1(b), produced an apparent slight decrease in cluster concentration, but annealing at 740°C, Fig. 1(C), resulted in a noticeable densification of the clusters. Finally, annealing at 900°C and 1040°C, Figs. 1(d) and (e), caused a definite decrease in cluster concentration and led to the formation of resolvable dislocation loops.

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X-Ray absorption edge elemental imaging of B. thuringienis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153038 ◽

1989 ◽

Vol 47 ◽

pp. 212-213

Author(s):

R. L. Stears

Keyword(s):

Absorption Edge ◽

Elemental Distribution ◽

X Rays ◽

Differential Absorption ◽

Synchrotron Source ◽

High Brightness ◽

X Ray ◽

Elemental Imaging ◽

Cellular Integrity ◽

X Ray Absorption

Because of the nature of the bacterial endospore, little work has been done on analyzing their elemental distribution and composition in the intact, living, hydrated state. The majority of the qualitative analysis entailed intensive disruption and processing of the endospores, which effects their cellular integrity and composition.Absorption edge imaging permits elemental analysis of hydrated, unstained specimens at high resolution. By taking advantage of differential absorption of x-ray photons in regions of varying elemental composition, and using a high brightness, tuneable synchrotron source to obtain monochromatic x-rays, contact x-ray micrographs can be made of unfixed, intact endospores that reveal sites of elemental localization. This study presents new data demonstrating the application of x-ray absorption edge imaging to produce elemental information about nitrogen (N) and calcium (Ca) localization using Bacillus thuringiensis as the test specimen.

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Microstructural characterization of sol-gel coating on PET films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172164 ◽

1994 ◽

Vol 52 ◽

pp. 886-887

Author(s):

R. T. Chen ◽

R.A. Norwood

Keyword(s):

Ion Beam ◽

Sol Gel ◽

Industrial Applications ◽

Hard Coatings ◽

Nanometer Scale ◽

Ion Beam Sputtering ◽

Process Technology ◽

Refractive Index Measurement ◽

Organically Modified ◽

Pet Films

Sol-gel processing has been used to control the structure of a material on a nanometer scale in preparing advanced ceramics and glasses. Film coating using the sol-gel process was also found to be a viable process technology in applications such as optical, porous, antireflection and hard coatings. In this study, organically modified silicate (Ormosil) coatings are applied to PET films for various industrial applications. Sol-gel materials are known to exhibit nanometer scale structures which havepreviously been characterized by small-angle X-ray scattering (SAXS), neutron scattering and light scattering. Imaging of the ultrafine sol-gel structures has also been performed using an ultrahigh resolution replica/TEM technique. The objective of this study was to evaluate the ultrafine structures inthe sol gel coatings using a direct imaging technique: atomic force microscopy (AFM). In addition, correlation of microstructures with processing parameters, coating density and other physical properties will be discussed.The materials evaluated are organically modified silicate coatings on PET film substrates. Refractive index measurement by the prism coupling method was used to assess density of the sol-gel coating.AFM imaging was performed on a Nanoscope III AFM (by Digital Instruments) using constant force mode. Solgel coating samples coated with a thin layer of Ft (by ion beam sputtering) were also examined by STM in order to confirm the structures observed in the contact type AFM. In addition, to compare the previous results, sol-gel powder samples were also prepared by ultrasonication followed by Pt/Au shadowing and examined using a JEOL 100CX TEM.

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