Nitrogen-rich plasma-polymer films for biomedical applications

Low-pressure plasma co-polymerisation of binary gas mixtures of ethylene and ammonia was investigated in order to deposit N-rich plasma polymer coatings for biomedical applications. Deposition kinetics and relevant surface characteristics were investigated as a function of r.f. power, gas pressure, and NH3/C2H4 ratio. Physico-chemical properties of the coatings were determined by surface-sensitive techniques: for example, total nitrogen concentrations up to 40 at.-% were measured by XPS, while those of primary amines were determined by chemical derivatisation followed by XPS analysis. L-PPE:N films were further characterised by UV-vis and IR spectroscopic ellipsometry and by CAG.