A Comparative Mass‐Spectrometric Study of Plasma‐ and Vacuum Ultraviolet Ablation of Selected Polymers

Abstract

Energetic photons (UV, VUV radiation and soft X rays), and particles (ions, electrons, metastable excited atoms) from inert gas plasmas possess sufficient energy to induce multiple bond scission reactions in the macromolecular chains of most polymers. As a result, volatile products of varying molecular weights escape from the polymers' surfaces; they can be captured and identified by mass spectrometry (MS). We report an MS-based study of five commercial polymers, polyethylene (PE), polypropylene (PP), polystyrene (PS), poly(ethylene terephthalate) (PET) and polyamide that were exposed to inert gas (He, Ar) plasmas and to near-monochromatic (l ¼ 121.6 nm) VUV irradiation. For the cases of PE and PP, quantitative analyses of the most abundant reaction products (H 2 , C 1 -C 7 alkanes) are compared among the various polymer/excitation-source cases, and with regard to literature data for g irradiation.

Inhibition of Interfacial Oxidative Degradation During SiOxPlasma Polymer Barrier Film Deposition on Model Organic Substrates

“…They concluded that a fragmentation/redeposition process during intial stages of the deposition lead to Si‐CH x bonds formed by the volatile organic species, intermixing with the precursor gas. Moreover, release of organic fragments from several commercial polymer surfaces was confirmed by Wertheimer et al, where mass‐spectroscopy was employed to analyse the fragments emerging upon exposure to inert gas plasmas and/or VUV (vacuum ultraviolet) photons …”

Challenges in the characterization of plasma polymers using XPS

“…Mainly focused on vacuum plasmas, a growing number of studies using mass spectrometry (MS) to characterize the gas phase during plasma deposition of organic [25,[36][37][38] and inorganic [39][40][41][42][43] coatings as well as during plasma etching/ablation of polymer surfaces [44,45] can be found in the literature. The above-cited references attest that, although MS does not provide direct, unambiguous chemical information due to possible fragmentation in the ionization chamber, one can easily discern fragmentation and/or oligomerization phenomena as soon as (in)organic molecules (precursor or monomer) are subjected to plasma discharges.…”

Modification of stearic acid in Ar and Ar-O2 pulsed DC discharge

“…In the figure, E is any energy source (i.e., photons produced by VUV and UV, energetic ions or electrons) that is capable of breaking bonds [15][16][17] . The formation of alkyl radicals (R • ) via reaction 2 can occur via the removal of hydrogen by oxygen 7 .…”