GENERATION OF NONEQUILIBRIUM PLASMA AT ATMOSPHERIC-PRESSURE AND APPLICATION FOR CHEMICAL PROCESS

When various oxide powders were prepared by microwave heating under an argon gas flow, we found that an atmospheric pressure non-equilibrium plasma generates around some powders. This phenomenon was peculiar to electrically conductive and heat-resisting materials. These plasmas c ould also be generated easily using gas mixtures consisting of argon a nd additive gases. With an eye towards industrial applications, we tri ed to modify the surface of substrates as application examples. The wa ter contact angles of substrates were varied by plasma surface modific ation. CF4/Ar plasma treatment of polypropylene film increased the con tact angle of water from 101 degrees to 124 degrees. The results indic ated that the polymer surfaces became highly hydrophobic. On the other hand, the contact angle of water decreased when O-2/Ar gas was used. (C) 1998 Published by Elsevier Science S.A.