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

• Published in: Plasma processes and polymers Vol. 7; no. 6; pp. 431 - 444
• Main Authors: Nelea, Valentin, Vasilets, Victor N., Skurat, Vladimir E., Truica-Marasescu, Florina, Wertheimer, Michael R.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 22-06-2010; WILEY‐VCH Verlag
• Subjects: mass spectrometry; surfaces
• ISSN: 1612-8850; 1612-8869
• DOI: 10.1002/ppap.200900148

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 (λ = 121.6 nm) VUV irradiation. For the cases of PE and PP, quantitative analyses of the most abundant reaction products (H2, C1–C7 alkanes) are compared among the various polymer/excitation‐source cases, and with regard to literature data for γ irradiation.
Mass spectrometry is used to investigate volatile products emanating from the surfaces of five commercial polymers, when the latter are ablated by exposure to (i) low‐pressure inert‐gas plasmas, and (ii) monochromatic vacuum ultraviolet (λ = 121.6 nm) photons. The mass spectra of polyethylene and polypropylene are interpreted semi‐quantitatively with regard to relative yields of H2 and C1–C7 alkanes, and the results are compared with those from the literature obtained under γ‐ray radiolysis.