Nitrogen-rich plasma polymers: Comparison of films deposited in atmospheric- and low-pressure plasmas

• Published in: Thin solid films 2008-09, Vol.516 (21), p.7406-7417
• Main Authors: Truica-Marasescu, Florina, Girard-Lauriault, Pierre-Luc, Lippitz, Andreas, Unger, Wolfgang E.S., Wertheimer, Michael R.
• Format: Article
• Language: English
• Subjects: Aging; Composition and phase identification; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition process; Electric discharges; Ethylene; Exact sciences and technology; Fourier transform infrared spectroscopy (FTIR); Glow discharge; Glow; corona; Ion and electron beam-assisted deposition; ion plating; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma applications; Plasma polymers; Plasma-based ion implantation and deposition; Surface chemistry; Surface energy; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2008.02.033

Low- and atmospheric-pressure plasma co-polymerisations of binary gas mixtures of C 2H 4 and NH 3 or N 2, respectively, were investigated for depositing N-rich plasma polymer coatings for biomedical applications. Deposition kinetics and relevant surface characteristics of resulting plasma polymerised ethylene enriched with nitrogen, “PPE:N”, coatings were investigated as a function of the gas mixture ratio, X = NH 3(N 2)/C 2H 4. Physico-chemical properties of the coatings were determined using a combination of complementary surface-sensitive techniques: for example, total nitrogen concentrations, [N], up to 40 at.% were measured by X-ray Photoelectron Spectroscopy, XPS, while those of primary amines, [–NH 2], were determined by performing chemical derivatisation followed by XPS analyses. PPE:N films were further characterised by UV–VIS Ellipsometry, Near Edge X-ray Absorption Fine Structure Spectroscopy, IR Spectroscopy and by Contact Angle Goniometry measurements. The stability of the coatings was tested, both in terms of water solubility and of “ageing” in ambient atmosphere. For the latter, selected samples were stored in the laboratory for different durations, in order to assess possible changes in their chemical structures.