Surface dielectric barrier discharges with patterned flexible and ultra-stretchable electrodes for low‑temperature plasma applications

Surface dielectric barrier discharge (sDBD) has been widely used across various fields, not only for traditional applications such as surface treatment and modification, but also for emerging uses in medical and agri-food sectors. To extend the applicability of sDBD for overcoming the limited applicability due to their rigid structure and form factor constraints, we introduce an inkjet-printed, thin-film flexible plasma source (f-DBD). The developed flexible plasma source can be applied to a wide variety of shapes via origami, maintaining stable plasma discharge even when bent. With optimized inkjet printing and passivation processes, the f-DBD device demonstrated a continuous operational lifetime of several hours. This plasma film, f-DBD, is operable in two distinct modes, ozone-dominant and nitrogen oxide-dominant modes. Expanding on this, we have newly developed a stretchable and flexible DBD (sf-DBD) plasma source, capable of withstanding 3D high-curvature bending and significant elastic deformation. The sf-DBD device was fabricated by printing liquid metal electrodes onto various elastomeric polymers. By selecting polymer materials with specific mechanical properties and thicknesses, we achieved stable plasma discharge even under 2.5 times the original length. The sf-DBD device demonstrated robust performance, sustaining stable plasma operation under complex 3D deformation for over 10 hours continuously. Furthermore, the liquid metal electrodes retained their functionality even several months after fabrication. The developed sDBD sources may be applicable to high-dimensional objects such as the human body.