Surface Hydrophilization of Polyimide Films Using Atmospheric Damage-Free Multigas Plasma Jet Source

Atmospheric-pressure plasma jet sources have proven useful for surface treatments; however, conventional plasma and near-plasma sources have limitations in the number of different plasma gas species that they can handle. We previously developed a damage-free multigas plasma jet source that can generate stable atmospheric-pressure plasma using various gas species without thermal/electrical discharge damage. Herein, we investigate the fundamental characteristics of the generated plasma such as gas temperature (<;57°C) and emission properties. In addition, we evaluate the industrial potential of the jet source by using it with various gas species to induce surface hydrophilization in a polyimide film. The jet source proved useful, and carbon dioxide proved the most effective of the studied gas species for the purpose with the hydrophilized surface maintaining a contact angle of about 30° for over 32 days after plasma irradiation.