Ion Beam Treatment of Polymers, 2nd Edition

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Wetting

Wettability is an important characteristic for polymer materials, and in some appli- cations a wettable surface is necessary. Typically, polymers have low surface energy compared with metals. After ion implantation, the water contact angle decreases significantly. The total surface energy increases from 20–40 MJ/m² for untreated polymers to 70–80 MJ/m² after ion implantation. The polar part of the surface energy increases significantly, while the dispersive part does not change much. After time exposed to atmosphere, the total energy and its polar part decreases, while the dispersive part remains relatively stable. The changes in surface energy after ion implantation are caused by the appearance of radicals in the surface layer that ...