Excimer laser ( λ = 193 nm) versus Al K α X-ray damages on polymer surfaces: an XPS (core and valence levels) analysis of polytetrafluoroethylene, polypropylene and polyethylene

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 1995-11, Vol.105 (1), p.186-191
• Main Authors: Pireaux, J.J., de Meulemeester, R., Roberfroid, E.M., Grégoire, Ch, Chtaïb, M., Novis, Y., Riga, J., Caudano, R.
• Format: Article
• Language: English
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/0168-583X(95)00548-X

The characterization of surface modifications of polymers, after irradiation with X-ray or UV photons, is abundant in the XPS literature, reporting from core level analysis the modification of surface chemical composition (loss of fluorine, or chlorine, or oxygen … content). This work focuses on the use of XPS valence band spectra to show that irradiation can lead to superficial structural modification — lateral chain grafting, or crosslinking — of so-called “reactive” (polytetrafluoroethylene) and even more “stable” (polypropylene and polyethylene) polymers: this is best evidenced by modification of the typical shape of the C 2s valence band. This structural modification appears more pronounced for high fluence UV excimer laser irradiation in air, than for (more moderate) exposition to harder X-rays in vacuo.