An Array of Micro-hollow Surface Dielectric Barrier Discharges for Large-Area Atmospheric-Pressure Surface Treatments

A robust, commercial micro-hollow plasma source was used to generate atmospheric-pressure plasma, of surface area 18 x 18 mm, in ambient air, nitrogen and argon. An electrode system consisting of 105 micro-hollow surface dielectric barrier discharges was powered by sinusoidal high-voltage at a frequency of 26.7 kHz. The influence of the plasmas on the polycarbonate surface was investigated by means of surface energy measurements and X-ray photoelectron spectroscopy. It emerged that short plasma exposures led to significant increases in surface energy. It is suggested that this may arise out of incorporation of polar groups on the polycarbonate surface. A thermal camera was used to monitor the plasma source surface temperatures for the gases at flow rates ranging from 0 to 5 L/min. It was found that the temperature of the micro-hollow ceramic when operated upon in ambient air decreased significantly from 147 A degrees C at 0 L/min to 49 A degrees C at 5 L/min. In order to investigate further the thermal properties of the plasma, optical emission spectroscopy was employed to monitor the vibrational and rotational temperatures of the plasma generated in ambient air. CCD camera spectroscopic measurements estimated plasma thickness and temperature distribution at high spatial resolution.