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A Time‐ and Angle‐Resolved X‐Ray Photoelectron Spectroscopy Study of Polystyrene Exposed to a Helium Plasma
Author(s) -
Paynter Royston W.,
Ménard Marc,
Benalia Hadjira
Publication year - 2004
Publication title -
plasma processes and polymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 74
eISSN - 1612-8869
pISSN - 1612-8850
DOI - 10.1002/ppap.200400016
Subject(s) - x ray photoelectron spectroscopy , irradiation , analytical chemistry (journal) , polystyrene , helium , oxygen , materials science , plasma , atomic physics , chemistry , physics , nuclear magnetic resonance , organic chemistry , chromatography , quantum mechanics , nuclear physics , composite material , polymer
Abstract Summary: Angle‐resolved X‐ray photoelectron spectroscopy (ARXPS) measurements were carried out, using Al K α and Mg K α radiation alternately, on a polystyrene sample that had been exposed to a helium plasma. It was observed that oxygen was introduced into the sample surface by the plasma treatment, and that some of it was lost over a period of 5 h under X‐ray irradiation in the vacuum of the spectrometer. The ARXPS data sets were corrected for the time displacement between consecutive measurements at different photoemission angles, and fitted with trapezoidal model depth profiles in order to extract simple oxygen concentration depth profiles, consistent with the data, as a function of time. The depth profiles were found to evolve in a consistent manner, indicating some loss of average concentration and especially thickness in the oxygen profile. In comparison with previously published results obtained using a helium/oxygen plasma, the oxygen loss was less severe. The results are also interpreted in terms of a model supposing the desorption of a highly oxidized oligomer layer created during the plasma exposure.Evolution of the apparent concentration of oxygen with Al K α radiation as a function of irradiation time and photoemission angle. Symbols: ARXPS data; lines: splines drawn through points calculated from fitted depth profiles.