A stationary plasma thruster for modification of polymer and ceramic surfaces

A stationary plasma thruster (SPT)-type source with high plasma density is introduced and its physical principle and structure are briefly summarized. As general characteristic performance of the gridless SPT plasma source, ion current density, its angular distributions and distribution of ions over energies for three working gases of Ar, N2 and O2 was examined and also compared with that of a conventional Kaufman-type grid ion source. In order to investigate the possible application of SPT for the surface modification, polymer and ceramic surfaces are irradiated by the low energy and high fluence ion beam generated from SPT. The wetting angle of polyimide is greatly reduced from 78° to 2-4° by the irradiation of reactive O2+ and N2O+ ions with an average energy of 180 eV. Furthermore when α-Al2O3 (0 0 0 1) is irradiated by N2+ ion of SPT source at various ion fluences, the formation of new AlON and AlN chemical bonding are identified by X-ray photoelectron spectroscopy. From the results, it is revealed that the SPT can be used as an effective ion source for the enhancement of surface energy of polymer and for the formation of functional groups on ceramic surface.