In contrast to other plasma modification processes of polymer surfaces, the bromination is very selective and shows a high yield in CBr groups. The most convenient bromination process was found using bromoform, which was thus preferred to elemental bromine, allyl bromide, vinyl bromide or tert‐butylbromide. The bromoform process give yields in CBr up to 40 CBr or more, with only 2–3% co‐introduction of O‐functionalities whereas allyl bromide results in yields of about 20 CBr and more, but in more than 10% oxygen‐containing by‐products. CBr groups serve as anchoring points for grafting of molecules, oligomers and pre‐polymers of diole or diamine character.

Polyglycerol (PG) coated polypropylene (PP) films were synthesized in a two-step approach that involved plasma bromination and subsequently grafting hyperbranched polyglycerols with very few amino functionalities. The influence of different molecular weights and density of reactive linkers were investigated for the grafted PGs. Longer bromination times and higher amounts of linkers on the surface afforded long-term stability. The protein adsorption and bacteria attachment of the PP-PG films were studied. Their extremely low amine content proved to be beneficial for preventing bacteria attachment.

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Since more than 40 years ammonia plasma exposure of polyolefins is used for introduction of primary amino groups. The selectivity of this reaction and the yield in primary amino groups was found to be low. Here, a prominent side-reactions of this process was investigated, the hydrogenation by NH 3 plasma. For identification of hydrogenation ammonia (NH 3 ) and deuterated ammonia (ND 3 ) were exposed to polyethylene (h-PE) and fully deuterated polyethylene (d-PE) as well as hexatriacontane (h-HTC) and fully deuterated hexatriacontane (d-HTC) as low-molecular weight model for PE. H-D exchange was assumed and detected by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), X-ray Photoelectron Spectroscopy (XPS), Attenuated Total Reflectance (ATR-FTIR) and 1 H and 2 H Nuclear magnetic Resonance. Results show a significant H-D exchange within the sampling depth of ATR (2.5 lm). However, N-and NH 2 introduction was limited to the topmost surface as shown by SIMS and XPS (a few nanometers).

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