Surface modification of poly(tetrafluoroethylene) by saddle field fast atom beam source

Abstract

The surface of poly(tetrafluoroethylene) (teflon, PTFE) was treated by saddle field fast atom beam (FAB) source in hydrogen, helium and nitrogen with about 1 kV accelerating voltage, up to an estimated particle fluence of 10 17 cm − 2 . The untreated and FAB-treated samples were characterised by XPS, Raman microspectroscopy, single pass topographic and multipass wear tests and water contact-angle measurements. According to XPS results, upon FAB-treatment the surface F/C value decreased drastically. Raman microspectroscopic measurements testified to the formation of a carbonised surface layer. The thickness of the graded, amorphous carbon-containing layer determined by in-depth Raman microspectroscopic analysis ranged between 5.5 ± 1 and 10.5 ± 1 μm. In addition to radiation damage, a decisive role of degradation induced by thermal effects and diffusion of reactive particles was suggested. The small scale wear resistance of the hydrogen and nitrogen FAB-treated samples improved in comparison with that of the untreated PTFE. The mean surface roughness increased for the treated samples in the order of N < He < H. Water contact-angle decreased upon FAB-treatment. The effect of increased wettability remained durable for at least three months.