Positive and negative ion desorption from PVC as studied by electron stimulated desorption

Mendes, Luiz A. Vieira; Magalhães, S.D.; Arantes, C.; Rocco, Maria Luiza M.

doi:10.1016/j.polymdegradstab.2007.02.013

Cited by 9 publications

(3 citation statements)

References 18 publications

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“…Positive and negative electron stimulated ion desorption (ESID) performed on PVC films as a function of the electron energy indicated that at higher electron energies, inner-shell ionization processes followed by Auger decay play an important role in the positive ion desorption of chlorine species. On the other hand, the formation of negative chlorine ionic species was strongly enhanced around the Cl 2p-edge [8].…”

Section: Introductionmentioning

confidence: 97%

“…Ion desorption generated by photoexcitation at shallow and deep core levels has already proved to be an attractive topic in surface science since it is a surface phenomena that allows to investigate composition, electronic structure and site-selective fragmentation. Mainly interested in fundamental aspects, our group has performed several previous studies using small chlorinated molecules [5] or polymers, such as poly(vinyl chloride) (PVC) and poly(vinyl dichloride) (PVDC) [6][7][8][9][10], using electrons or high energy photons as excitation sources. In particular, our previous photon stimulated ion desorption (PSID) studies performed on PVC and PVDC films with photon energies covering the valence, Cl 2p and C 1s energy ranges showed element-selectivity as evidenced by an increase in the chlorine ion yield around the Cl 2p-edge as compared to the other excitation energies.…”

Section: Introductionmentioning

confidence: 99%

“…In the present study, NEXAFS (Near-edge X-ray absorption fine structure) and PSID spectra were acquired at the chlorine 1s-edge for PVC and PVDC, two chlorinated polymers containing a different number of chlorine atoms, in order to gain insight into the photofragmentation process induced by a deep core level, by comparing the contributions from direct (Auger) and indirect (secondary electrons) mechanisms to ionic desorption. Also the purpose of the work is to complement fragmentation studies performed previously on these films covering other energy intervals, ranging from valence to shallow inner-shell excitations [6][7][8][9][10]. The Cl 1s-edge was selected in order to evaluate possible improvements in the site-selectivity fragmentation of the C-Cl bond caused by chlorine core-shell excitation, since it is expected that excitation of localized electrons may favor selective bond breaking.…”

Section: Introductionmentioning

confidence: 99%

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Site-selective photofragmentation of chlorinated polymeric films observed around the chlorine K-edge

et al. 2013

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Photon stimulated ion desorption (PSID) and Near-edge X-ray absorption fine structure (NEXAFS) studies have been performed on poly(vinyl chloride) (PVC) and poly(vinyl dichloride) (PVDC) around the chlorine 1s-edge. Experiments were performed using a synchrotron source operating in the single-bunch mode and a time-of-flight mass spectrometry for ion analysis. Cl + ion yields, as a function of the photon energy, reproduce the photoabsorption spectrum, showing significant increase at the 1s-resonance. Edge-jump ratios, defined as the ratio between edge-jumps (intensity ratio of the yields between above and below the absorption edge) of two different transitions, for Cl + ion yields were much higher than the equivalent electron yields, indicating site-selectivity in C-Cl bond breaking for both polymers, as a result of efficient spectator Auger decay. The expected isotope ratio of 3:1 for chlorine was measured for PVC. The interpretation of the NEXAFS spectrum was assisted by quantum mechanical calculations at a multireference perturbation theory level.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Site-selective photofragmentation of chlorinated polymeric films observed around the chlorine K-edge

et al. 2013

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Organic-Inorganic Behavior of Plasma-Polymerized Hexamethyldisiloxane Films Studied by Electron and Photon Induced Ion Desorption

Veiga

Garcia-Basabe

Schmittgens

et al. 2013

Plasma Process. Polym.

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In the present work two thin films, fabricated by plasma-polymerization of hexamethyldisiloxane (HMDSO) monomer, were studied by a combination of electron (ESID) and photon (PSID) stimulated ion desorption techniques. The organic character of the polymer film is evidenced by the high contribution of C 2 H þ n species and the absence of high mass fragments in its ESID spectrum. On the other hand, the inorganic character is elucidated by the presence of high mass silicon ionic fragments. NEXAFS and PSID spectra also show clear differences between organic and inorganic films. The marked reduction of CH þ 3 species for PSID spectra of the organic-polymeric film is in accordance with ESID analysis and may be interpreted by a screening effect of its cross-linked organic structure.

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Desorption from methanol ice induced by electrons from solar wind or magnetospheres

Bergantini¹,

Andrade²,

Pilling³

et al. 2013

Advances in Space Research

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Positive and negative ion desorption from PVC as studied by electron stimulated desorption

Cited by 9 publications

References 18 publications

Site-selective photofragmentation of chlorinated polymeric films observed around the chlorine K-edge

Site-selective photofragmentation of chlorinated polymeric films observed around the chlorine K-edge

Organic-Inorganic Behavior of Plasma-Polymerized Hexamethyldisiloxane Films Studied by Electron and Photon Induced Ion Desorption

Desorption from methanol ice induced by electrons from solar wind or magnetospheres

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