Chemical and physical properties of copper and nitrogen plasma-implanted polyethylene

Plasma immersion ion implantation (PIII) is a new technique used to modify the surface physical and chemical properties of polymers for antibacterial purposes. Our previous research work has shown that copper and nitrogen PIII can give rise to excellent antibacterial properties on polyethylene (PE) substrates. In this paper, the effects of the PIII conditions on the chemical and physical properties of the Cu and N plasma-implanted PE are investigated. Elemental depth profiles show that Cu and N PIII results in the formation of C-N, C=N bonds in the surface region, and that the implanted Cu does not bond with the polymer matrix elements. A longer PIII time increases the concentrations of C≡N, C=N and C-N bonds formed in the near-surface region, but the elemental chemical states deeper into the sample remain about the same for different PIII time durations. However, if N-PIII and Cu-PIII are not carried out simultaneously, for example, N-PIII following Cu-PIII, the retained Cu dose is affected due to nitrogen sputtering, but the Cu chemical state is not altered. In addition, more C=N and C≡N bonds are formed in the outer surface region. A longer N-PIII implantation time further enriches these chemical functional groups. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.