INVESTIGATION ABOUT THE CHANGE OF SURFACE WITH TIME ON MODIFYING THE PLASTIC SURFACE BY COLD PLASMA AND ITS REDUCTION METHOD

The plastic films are modified by various plasmas (CF4, O2, Ar, N2) in order to know the difference of effects by kinds of their plasmas and the condition of the change of the surface characteristics with time after each plasma treatment is investigated in detail. Moreover, we developed the reduction method of its change with time. The condition of the surface modification by Ar plasma is similar to that of N2 plasma. But, that by O2 plasma was different from them. This reason is that the modification source is mainly ions on Ar plasma or N2 plasma, and radicals on O2 plasma. The contact angle modified by Ar plasma (N2 plasma) became smaller than that by O2 plasma; 0° (Ar plasma), 35° (O2 plasma). The contact angle after the plasma treatment was seldom reduced even if time passed when plastic film was treated by Ar plasma treatment with heating. The bounding property of oxygen atoms was controlled by heating in the plasma treatment. On the other hand, the change with time was not reduced by CF4 plasma with heating. But, treatment effect had been slightly increased. It is considered that the fluorine atoms which are causes of hydrophobic property are introduced much, however, are removed much.