Characteristic of surrounding gas-fed atmospheric pressure plasma jet and its application to surface treatment

We have developed the surrounding gas-fed plasma jet using a double coaxial glass tube to increase and control the production of active species in the plasma jet. Two gas flows can introduce independently into the tube and the gas and plasma flows interact outside of the glass tube. The developed plasma jet was compared with the conventional plasma jet with single glass tube by using optical emission spectroscopy. With an outer nitrogen (N₂) and an inner helium (He) gas flows, emission lines of nitric oxide, the first negative and second positive system bands of N₂ were observed, while emission line of nitric oxide was not observed in the single glass tube. The double coaxial glass tube makes a laminar flow and enhances the effective reaction area, resulting in energetic nitrogenous productions. We also evaluated the hydrophilic property of polyethylene terephthalates treated by the surrounding gas-fed plasma jet. (author)