Polyethylene, poly(propylene), and polyester were treated with sulfur dioxide plasma and with plasmas using a mixture of SO2 with oxygen or with hydrogen. Depending on the process gas and the treatment conditions the functional groups formed by the plasma treatment can be sulfides or groups with highly oxidized sulfur such as sulfonic acid groups and sulfates. XPS and infrared reflection absorption spectroscopy (IRRAS) were used to identify the surface functional groups. The acidic groups (sulfonic acid, hydrogen sulfates) were quantified by fluorescence labeling with dansyl cadaverine. Values of up to 820 pmol · cm−2 were found. The acidic functional groups were also used as starting points for further functionalization of the surfaces. In the reaction with diamino ethane, primary amines were produced on the surface.

Over the last 40 years we have witnessed an impressive development of the tools for the analysis of polymer surfaces. However, there still are questions, which are very challenging and the quest of answering these questions means working at the frontier of current science. We discuss some general features of the surfaces of synthetic polymeric materials and the new features formed in surface treatments. It is extremely difficult and in many cases virtually impossible to determine the concentration of all the chemical species present in such complex materials. The determination of their vertical distribution, i.e. the depth profile of these concentrations, is even more complicated. A new situation has arose since more and more surface functionalization techniques have gone from the laboratory to the production line. Microarrays are a good example. The quality control of the production is a challenging and sometimes expensive task.The combination of surface chemical reactions with instrumental techniques has been proven to be a valuable tool for surface analysis. After discussing some recent progress in that field we present examples that demonstrate a continuous progress in that field. The fluorescence dye Fluram can be used to determine the concentration of NH 2 groups at a surface and their local density. Nitric oxide can be used to determine radicals in polymer surfaces, also in the presence of oxygen. The trifluoroacetic anhydride (TFAA) derivatization of hydroxyl groups provides reliable data. The diffusion of fluoresceine isothiocyanate (FITC) labelled globuline was used to characterize the network density of surface coupled hydrogels.

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In plasma treatments, the process gas is usually fed into the chamber in a more or less continuous way. The pulsing of the process gas can provide new opportunities. Some of them are explored in this paper. The interrupted or alternating process gas flux can help in mixing the sample in an activation treatment of a polyethylene powder. If the pores are not too small, a pressure pulse can help to improve the oxidation inside a porous polyolefin material. A plasma polymerization of ethene or allylamine can be more efficient if the timing of a plasma power pulse and the monomer pulse is optimized. Radicals are formed in the surface during the plasma pulse and these radicals initiate a polymerization of the monomer at a higher pressure.