A stationary plasma thruster for modification of polymer and ceramic surfaces

Abstract

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, N-2 and O-2 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 degrees to 2-4 degrees by the irradiation of reactive O-2(+) and N2O+ ions with an average energy of 180 eV. Furthermore when alpha-Al2O3 (0001) is irradiated by N-2(+) ion of SPT source at various ion fluences, the formation of new Al-ON and Al-N 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. (c) 2005 Elsevier B.V. All rights reserved.