Influence of ring electrodes covered with dielectric layer on the characteristics of atmospheric pressure plasma jet and its interaction with polymer surface

• Plasma jet with ring electrodes covered with dielectric layers (DL) was investigated. • The addition of DL can improve the uniformity of electric field distribution. • DL addition can reduce the current intensity and decrease the intensity of the reactive species. • Etching morphologies of polymer films can be improved after DL addition. • Oxygen content in the etched region decreases rapidly with the addition of DL. Atmospheric pressure plasma jet (APPJ) with ring-ring typed electrode configuration is widely utilized in material processing and biomedical applications. In this paper, the ring electrodes covered with dielectric layer (DL) is proposed for improving its electric field distribution and controlling the plasma characteristics and its interaction with polymer film. Simulation and experiment method was used to investigate the effect of the DL addition on the characteristics of plasma jet and plasma etching of polymer film. Simulation result indicates that DL addition can not only improve the uniformity of electric field distribution, but also reduce its intensity in the tube. The experimental results show that DL addition can reduce the plasma current intensity and decrease the intensity of the reactive species. Compared with bare ring electrodes, polymer etching morphologies are greatly improved after DL addition. Besides, the oxygen content in the etched region also decreases rapidly with DL addition, and the larger the dielectric constant is, the larger the O/Si and O/C ratio is. The interaction process between APPJ and polymer film was also discussed and the improvement of electrical field distribution was considered as the main reason for the results of plasma discharges and its interaction with polymer film.