Surface characterization of ultrahigh molecular weight polyethylene after nitrogen ion implantation

• Published in: Surface and interface analysis Vol. 30; no. 1; pp. 434 - 438
• Main Authors: Tóth, A., Bertóti, I., Szilágyi, E., Dong, H., Bell, T., Juhász, A., Nagy, P. M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.08.2000; Wiley
• Subjects: Applied sciences; Coating, metallization, dyeing; ERDA; Exact sciences and technology; FTIR; ion implantation; Machinery and processing; Plastics; polyethylene; Polymer industry, paints, wood; RBS; Technology of polymers; ultra-microhardness; XPS; Polyethylene; Ion implantation; Fluence; Nitrogen ion; X ray; Experimental study; Microhardness; Surface treatment; Surface structure; Structure processing relationship; Rutherford backscattering; Analysis method; Photoelectron spectrometry
• ISSN: 0142-2421; 1096-9918
• DOI: 10.1002/1096-9918(200008)30:1<434::AID-SIA788>3.0.CO;2-W

Ultrahigh molecular weight polyethylene (UHMWPE) samples were implanted with 46 and 80 keV nitrogen ions up to a fluence of 1017 ions cm−2. The modified surface layers were studied by XPS, Fourier transform infrared spectroscopy (FTIR), Rutherford backscattering spectrometry, elastic recoil detection analysis and dynamic ultra‐microhardness measurements. By XPS at relatively low fluences (∼1015 ions cm−2) the dominant N 1s peak component was detected at ∼400 eV, which was attributed to C–N‐type bonds. With increasing fluence the share of component at ∼398.5 eV, assigned to C–N‐type bonds, increased significantly. Changes in the FTIR spectra reflected dehydrogenation (creation of trans‐vinylene groups) and oxidation (creation of carbonyl groups). Rutherford backscattering spectrometry allowed the depth profiles of the elements to be obtained. In each case, the thickness of the oxygen‐containing layer proved to be greater than that of the nitrogen‐containing layer. Elastic recoil detection analysis revealed the formation of a layer with a characteristically graded hydrogen depletion. The thickness of this layer was greater than the projected range of the nitrogen ions. Significant improvement in the surface hardness was observed for the ion‐implanted UHMWPE in the whole range of indentation depth studied. Copyright © 2000 John Wiley & Sons, Ltd.