Publication details
Plasma Activation of Polymers by Diffuse Coplanar Surface Barrier Discharge and Low Pressure Ion Bombardment
| Authors | |
|---|---|
| Year of publication | 2013 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | The polymers are important material for many applications from the flexible electronics (displays, solar cells) to biocompatible materials for implants and tissue engineering. Surface modifications of PET, PEN, PMMA and PEEK polymers by the atmospheric low cost DBD plasma discharge in ambient air and nitrogen at atmospheric pressure were studied. The samples were treated in the 400 W powered DBD plasma discharge. The samples were exposed directly to the plasma. The treating time was from 1 s up to 10 s. A comparison was made to low pressure experiments with oxygen and argon, nitrogen and air ions from MW plasma source (Tectra Sputter Gun) at energies from 100 eV up to 2500 eV. The surface modifications were investigated by various surface sensitive techniques for example XPS, the contact angle measurement for surface energy evaluations, FTIR, AFM and the electro kinetic potential was also investigated on the modified surfaces over wide range of pH. For example, the DBD plasma treatment on PEN had no significant influence on the surface morphology. But the water contact angle was reduced by the treatment form initial 79 to 31 (air) and 20 (nitrogen) when after 3 day at normal conditions the contact angles was still about 50 and 40, respectively. The oxygen concentration in the PEN foil measured by XPS was increased from an initial 22 at. % up to 45 at. % after first 5s in DBD air plasma. The nitrogen DBD plasma modified surface composition only by implanted nitrogen up to 5 at. %. But the surface modifications in air plasma resulted in the formation of new chemical bonds between the carbon and the oxygen, e.g., C=O, O–C–O. The O-C bond was reduced significantly on the treated surface. The physical sputtering process was dominant for the treatment by argon ions at both energies and oxygen ions treatment at higher energy 2.5 kV in low pressure conditions. The O/C ratio evaluated on PEN surface decreased fast from initial value about 0.29 to 0.19 and 0.09 by argon ions treatment with energy 0.2 keV and 2.5 keV, respectively. In contrary the low energy 0.2 keV oxygen ions treatment can increase O/C ratio up to 0.43. The argon ions treatment was the physical sputtering process with the preferential removal of oxygen when the oxygen ions treatment had both physical interactions and chemical reactions. The 2.5 keV oxygen ions treatment modified the PEN surface dominantly by physical interactions therefore the O/C ratio was reduced but certain increase in relative abundance in C-O bonds was observed. The 0.2 keV oxygen ions treatment also faster increases C-O bond then C=O bonds but they are in contrary to other treatments also increased. The surface modification under various condition evaluated together gives opportunity to compare those techniques under identical conditions. |