ABSTRACT
HDPE films were treated in the post-discharge region of N2/O2 plasma, powered by a radio frequency power supply. Therefore, in this paper, it was investigated the role of pressure in molding the nano-topography of the polymer. The treatment was carried out in low temperature (T <40 ° C) and time of 5.0 min, in order to preserve the integrity of the polymer bulk. It is well known that the production and recombination rate of reactive species in the plasma depends on the working gas pressure. Results show that the surface nano-roughness is very sensitive to pressure, between 0.01Torr and 0.5Torr, making it possible to use as a fine control parameter for polymer nano-texturing. In the lower pressure treatment it was observed regular nano-peaks and nano-troughs on the surface of the sample. Contact angle measurements show that, in general, the surface becomes hydrophilic after N2/O2 plasma treatment. In addition, samples treated in higher pressure generate oxidized islands by the action of the oxidizing plasma. All samples became more hydrophilic after plasma treatment, maintaining this hydrophilicity characteristic for several days.
Keywords
HDPE polymer; N2/O2 plasma; roughness
