| AVS 55th International Symposium & Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS1-ThM |
| Session: | Atmospheric Plasma Processing and Micro Plasmas |
| Presenter: | W. Graham, Queens University Belfast, Northern Ireland |
| Authors: | W. Graham, Queens University Belfast, Northern Ireland D. Della Croce, Queens University Belfast, Northern Ireland L. Schaper, Queens University Belfast, Northern Ireland L. O'Neill, Dow Corning Plasma Solutions, Ireland A.M. Hynes, Dow Corning Plasma Solutions, Ireland |
| Correspondent: | Click to Email |
Time and space-resolved electrical, optical and imaging characterisation of a commercial, 1800cm2 atmospheric pressure plasma system, operating with polymer film is reported. . The system is based on a dielectric barrier discharge operated in air with flowing helium. The system is optimized for plasma treatment, rather than the physical appearance of the plasma. The Dow Corning Plasma Solutions LabLine™ system establishes discharges in two back to back, identical 340mm x 300mm transparent, electrode structures each with an inter-electrode gap of 5mm. The driving power supply produces a sinusoidal voltage, of up to 20 kV peak to peak, at frequencies of around 20 kHz. This is applied to the two internal electrodes. The outer electrodes are grounded. Helium is introduced from the top of the electrodes. Polyethylene Terephthalate (PET) polymer film could be suspended in the centre of the electrode gap, parallel to the glass dielectrics. Standard high voltage and current measurement techniques were used monitor the voltage applied to the electrodes and the current (Id) drawn through the power cable to the electrode assembly. A fast photomultiplier tube was used to measure the temporally resolved emission from the discharge while the spatially and temporally resolved behaviour of the discharge was studied by imaging the electrodes and the electrode gap onto a gated ICCD. The imaging indicates that with or without polymer film present, static or moving, radially uniform discharges, persisting for a few microseconds, are consistently created at the same phases of the applied voltage. The number of discharges increases with increasing input power and hence applied voltage. The structure of the discharge emission is suggestive of that of an atmospheric pressure being most intense at the cathode and showing evidence of a dark space and much less intense emission beyond that. At higher input powers, when the applied voltage considerably exceeds the initial breakdown voltage, these discharges occur so frequently that they sustain and enhance these structured discharges for periods of up to 25 μs. In the presence of the polymer film the discharge was generally more intense in the region occupied by the film and always produced emission between the polymer and the cathode. The authors wish to thank Dr. D. Dowling and B. Twomey of U.C. D. for their support and assistance and gratefully acknowledge EPSRC and Dow Corning support for of D. D. C.