Plasma co-polymerisation of ethylene, 1,3-butadiene and ammonia mixtures in a low pressure capacitively coupled r.f. glow discharge is investigated to produce amine-rich stable plasma polymer films for biomedical applications. Deposition kinetics, surface chemistry and water stability of films are studied as a function of r.f. power and precursor gas flow ratios. The surface primary amine content is evaluated by chemical derivatisation with 4-trifluoromethyl benzaldehyde followed by XPS; and stability by profilometric measurements of film thickness loss after 24 h of immersion in DI water. Multivariate regression analyses are used to obtain empirical models for N content and stability. Results show a clear improvement in performance in films containing butadiene as compared to the ethylene based films. (C) 2015 Elsevier B.V. All rights reserved.