Atmospheric pressure plasma jet for surface treatment: a review

Atmospheric pressure plasma jet (APPJ) is one of the primary sources to produce low-temperature plasmas that are commonly characterized with low gas temperature and high species reactivity, thus possessing wide application prospects in various fields including bio-medicine and materials. Compared to other low-temperature plasma sources such as parallel plate DBDs or surface DBDs, APPJs are featured with a plasma plume formed in ambient atmosphere other than confined in between electrodes, making it suitable for surface treatment, especially the one with complex surface morphology. Generally, APPJs can alter the surface properties via multiple physical and chemical mechanisms, such as surface charging, surface ionization waves, surface reactions, etc., and in turn, the surface properties, such as surface morphology, permittivity, and conductivity, could affect the discharge dynamics in APPJs. Interactions between APPJs and surfaces are therefore not only scientific issues on discharge plasma physics, but also technical challenges for specific applications, and gaining great research interests in the past three decades. In the present work, we aim to provide an educational review on the interactions between APPJs and surfaces, focusing on the physical, chemical and biological processes in both fundamental science and application engineering.