High-Energy Spectroscopic Studies of the Electronic Structures of Organic Systems Formed from Carbon and Fluorine by UPS, Vacuum-UV Optical Spectroscopy, and NEXAFS: Poly(hexafluoro-1,3-butadiene) [C(CF3) = C(CF3)] n , Fluorinated Graphites (CF, C2F, and C6F), Perfluoroalkanes n-C n F2n+2, Poly(tetrafluoroethylene) (CF2) n , and Fluorinated Fullerenes (C60F <

Seki, Kazuhiko; Mitsumoto, R.; Ito, Eisuke; Araki, Tohru; Sakurai, Yasuhisa; Yoshimura, Daisuke; Ishii, Hisao; Ouchi, Yukio; Miyamae, Takayuki; Narita, Tadashi; Nishimura, Shin; Takata, Y.; Yokoyama, Toshihiko; Ohta, Toshiaki; Suganuma, Shigeaki; Okino, Fujio; Touhara, Hidekazu

doi:10.1080/10587250108023664

Cited by 21 publications

(18 citation statements)

References 35 publications

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“…In contrast to our results, the CK edge spectrum of high-temperature-produced (C 2 F) n showed a very small intensity around 285 eV, confirming that almost all carbon atoms composing the layers are in the sp 3 -hybridized state. 31 The peak B at 288.5 eV with a shoulder C around 290 eV should be related to the 1sfσ* transitions within carbon atoms bonded with fluorine. Actually, the peaks around 288.7 and 290 eV have been observed in the NEXAFS spectra measured near the CK edge of fluorinated activated carbon fibers 57 and fluorinated carbon nanotubes.…”

Section: Resultsmentioning

confidence: 98%

“…Thus, measuring the NEXAFS spectra near the CK and FK edge of graphite fluorides (CF) n and (C 2 F) n synthesized at high temperatures, Seki et al observed the angular dependence of the peaks corresponding to σ*(CF) excitations. 31 This dependence was ascribed to near vertical orientation of CÀF bonds relative to the carbon skeleton. However, the much stronger changes in the spectra are characteristic for anisotropic materials possessing a π system, such as graphite, 32 hexagonal BN, 33 aligned carbon nanotubes, 34 graphene, 35 and graphene oxide films.…”

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confidence: 99%

“…The bond orientation is detected from changes in the intensity of corresponding resonances with the incident-polarized X-ray radiation. Thus, measuring the NEXAFS spectra near the CK and FK edge of graphite fluorides (CF) n and (C 2 F) n synthesized at high temperatures, Seki et al observed the angular dependence of the peaks corresponding to σ*(CF) excitations . This dependence was ascribed to near vertical orientation of C–F bonds relative to the carbon skeleton.…”

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Anisotropy of Chemical Bonding in Semifluorinated Graphite C₂F Revealed with Angle-Resolved X-ray Absorption Spectroscopy

et al. 2012

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Highly oriented pyrolytic graphite characterized by a low misorientation of crystallites is fluorinated using a gaseous mixture of BrF(3) with Br(2) at room temperature. The golden-colored product, easily delaminating into micrometer-size transparent flakes, is an intercalation compound where Br(2) molecules are hosted between fluorinated graphene layers of approximate C(2)F composition. To unravel the chemical bonding in semifluorinated graphite, we apply angle-resolved near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and quantum-chemical modeling. The strong angular dependence of the CK and FK edge NEXAFS spectra on the incident radiation indicates that room-temperature-produced graphite fluoride is a highly anisotropic material, where half of the carbon atoms are covalently bonded with fluorine, while the rest of the carbon atoms preserve π electrons. Comparison of the experimental CK edge spectrum with theoretical spectra plotted for C(2)F models reveals that fluorine atoms are more likely to form chains. This conclusion agrees with the atomic force microscopy observation of a chain-like pattern on the surface of graphite fluoride layers.

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Anisotropy of Chemical Bonding in Semifluorinated Graphite C₂F Revealed with Angle-Resolved X-ray Absorption Spectroscopy

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“…3), which could be ascribed to the σ * (C-F). 21 It can be understood that the appearance of the new peak is a consequence of the formation of a C-F bond at the expense of a π bond between the carbon atom attacked by a fluorine atom and the carbon atom adjacent to it. Interestingly, upon fluorination, an extra peak (p2) at 284.9 eV was created in addition to the edge-state peak (p1) and the π * -conduction band.…”

Section: Magnetic Edge and Dangling Bond State On Fluorinated Acfsmentioning

confidence: 99%

Magnetic edge state and dangling bond state of nanographene in activated carbon fibers

et al. 2011

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The electronic structure of nanographene in pristine and fluorinated activated carbon fibers (ACFs) have been investigated with near-edge x-ray absorption fine structure (NEXAFS) and compared with magnetic properties we reported on previously. In pristine ACFs in which magnetic properties are governed by nonbonding edge states of the π electron, a prepeak assigned to the edge state was observed below the conduction electron π * peak close to the Fermi level in NEXAFS. Via the fluorination of the ACFs, an extra peak, which was assigned to the σ -dangling bond state, was observed between the prepeak of the edge state and the π * peak in the NEXAFS profile. The intensities of the extra peak correlate closely with the spin concentration created upon fluorination. The combination of the NEXAFS and magnetic measurement results confirms the coexistence of the magnetic edge states of π electrons and dangling bond states of σ electrons on fluorinated nanographene sheets.

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“…Certainly, no fluorine was observed in the oxygen plasma treated sample, but a distinctive peak at F K-edge was observed for the sample treated by CF 4 plasma (Figure 9). Seki et al performed systematic research on F K-edge NEXAFS of various C–F systems and found rich structures [53]. In our case, the structure is pronounced but broad including both transitions with F 1s→π* and F 1s→σ* characteristics.…”

Section: Resultsmentioning

confidence: 50%

Degradation of Albumin on Plasma-Treated Polystyrene by Soft X-ray Exposure

et al. 2016

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Thin films of human serum albumin (HSA) were immobilized on polystyrene (PS) substrates previously functionalized either with polar or nonpolar functional groups. The functionalization was performed by treatment with cold gaseous plasma created in pure oxygen and tetrafluoromethane (CF 4 ) plasmas, respectively. Samples were examined with soft X-rays in the photon energy range of 520 to 710 eV in the ANTARES beam line at SOLEIL Synchrotron. NEXAFS spectra of O K-edge and F K-edge were collected at different spots of the sample, and measurements at each spot were repeated many times. A strong degradation of the HSA protein was observed. The weakly irradiated samples exhibited strong absorption at 531.5 eV associated with the O 1sÑπ* amide transitions, and a broad non distinctive peak at 540 eV was attributed to the O 1sÑσ* C-O transitions. Both peaks decreased with increasing irradiation time until they were completely replaced by a broad non-distinctive peak at around 532 eV, indicating the destruction of the original protein conformation. The shortage of the amide groups indicated breakage of the peptide bonds.

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Cited by 21 publications

References 35 publications

Anisotropy of Chemical Bonding in Semifluorinated Graphite C₂F Revealed with Angle-Resolved X-ray Absorption Spectroscopy

Anisotropy of Chemical Bonding in Semifluorinated Graphite C₂F Revealed with Angle-Resolved X-ray Absorption Spectroscopy

Magnetic edge state and dangling bond state of nanographene in activated carbon fibers

Degradation of Albumin on Plasma-Treated Polystyrene by Soft X-ray Exposure

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Cited by 21 publications

References 35 publications

Anisotropy of Chemical Bonding in Semifluorinated Graphite C2F Revealed with Angle-Resolved X-ray Absorption Spectroscopy

Anisotropy of Chemical Bonding in Semifluorinated Graphite C2F Revealed with Angle-Resolved X-ray Absorption Spectroscopy

Magnetic edge state and dangling bond state of nanographene in activated carbon fibers

Degradation of Albumin on Plasma-Treated Polystyrene by Soft X-ray Exposure

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Anisotropy of Chemical Bonding in Semifluorinated Graphite C₂F Revealed with Angle-Resolved X-ray Absorption Spectroscopy

Anisotropy of Chemical Bonding in Semifluorinated Graphite C₂F Revealed with Angle-Resolved X-ray Absorption Spectroscopy