Surface treatment of polyethylene by fast atom beams

• Published in: Solid state ionics Vol. 141-142; pp. 225 - 229
• Main Authors: Ujvári, T., Tóth, A., Bertóti, I., Nagy, P.M., Juhász, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2001
• Subjects: a-CNx:H; FAB; Microhardness; N atoms; Polyethylene; XPS; Polyethylene; XPS; a-CNx:H; Microhardness; FAB; N atoms
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/S0167-2738(01)00750-0

Ultra-high molecular-weight polyethylene (UHMWPE) was treated by fast atom beams (FAB) obtained from He, Ar, H2 and N2 with about 1 kV accelerating voltage and estimated fluence of 1017 particles cm−2. The modified surface layers were characterised by X-ray photoelectron spectroscopy (XPS or ESCA) and dynamic microhardness measurements. Each applied FAB treatment results in the increase of the bulk plasmon loss energy (EL) of the C 1s peak. This implies the formation of graphitic-type material and/or hydrogenated amorphous carbon (or carbon nitride in case of treatment by N atoms) in the modified surface layer. FAB treatment by N atoms leads to the incorporation of ≈35 at.% of N, which is about three times higher than the value obtained previously after low-kilo-electron-volt N2+ ion-beam treatment. The related C 1s peak shows that the overwhelming portion of C is bound to N, while the N 1s peak reflects that N is present in at least three chemical bonding states. Angle-dependent XPS studies of the nitrogen-FAB-treated UHMWPE reveal the presence of a N-rich subsurface layer with a topmost layer containing less N. This is in agreement with the calculated depth distribution of N atoms. Each applied FAB treatment leads to significant increase in the surface microhardness.