Low Temperature Microplasma Jet at Atmospheric Pressure for Inducing Surface Modification on Polyethylene Substrates

Abstract

An atmospheric pressure ac microplasma jet device with Cu spiral-torsion-spring type electrodes was developed. This electrode geometryenables the generation of low power and stable micro plasma jet operated in Ar, He, O2, N2 and air at flux rates ranging from 2 to 12 L/min, applying an ac high voltage at 60Hz frequency. Moreover, the device is absent of dielectric parts which prevents contamination of the plasma. To observe the outflow pattern a Schlieren photography system was used, resulting in broaden and continuous laminar gas flow. Optical emission spectroscopy measurements allow us to infer the mean gas temperature of plasma jet from the outer electrode along its axial position. A temperature decrease of 110℃ to 40℃ was observed up to 5 mm and beyond this gas temperature the plasma jet reaches room temperature, so enabling it to use in treatment of heat-sensitive surfaces such as biomaterials and polymers like polyethylene.