The Role of Crystallinity on Polymer Interaction with Oxygen Plasma

In order to study the role of polymer crystallinity, we performed oxygen plasma treatment experiments on amorphous and semicrystalline poly(ethylene terephthalate) (PET) polymers. The samples were treated in weakly ionized, highly dissociated RF oxygen plasma in glow region for different exposure times. We found that the degree of polymer crystallinity has an influence on the recombination probability of neutral atoms which interact with the surface. For amorphous polymers the recombination coefficient is in the range from 8.3 x 10(-4) to 2.1 x 10(-4) and for semicrystalline from 4 x 10(-4) to 2.5 x 10(-5). The degree of crystallinity in plasma processing also has influences on surface topography, formation of new functional groups, etching and hydrophobic recovery (ageing). Therefore, the polymer crystallinity should be taken into consideration when optimizing plasma treatment processes for industry as well as for accounting neutral atom recombination on polymer surfaces.