Effect of HMDSO Addition on Discharge Characteristics and Uniformity of Nanosecond-Pulsed Plasma Jet Array

Atmospheric-pressure plasma jet (APPJ) array is considered as an efficient method to enlarge treatment and improve treatment efficiency. With the addition of precursors containing Si, the APPJ array can be used for improving the surface hydrophobicity and insulating performance of insulating materials. In this article, the influence of hexamethyl disiloxane (HMDSO) addition on the discharge characteristics and uniformity of a 1-D nanosecond-pulsed jet array in Ar has been investigated through electrical and optical methods. It is found that the addition of HMDSO in a small amount can promote the plume length, discharge power, transported charge, and emission intensity through the Penning effect. When the HMDSO content is higher than 0.04%, the discharge of jet array is weaken, especially the middle unit, which results in the decrease of the uniformity, plume length, discharge power, transported charge, and emission intensity. With the intensified charge-coupled device (ICCD) measurement of the ionization wave propagations of jet arrays in pure Ar, 0.04%, and 0.50% HMDSO, it shows that the 0.04% HMDSO enhances the spatial electric field strength in jet array and promotes plasma bullets propagation. However, more HMDSO addition reduces the space charges and plasma bullets propagation speed. The competition of Penning effect and electron absorption by the HMDSO addition results that the Ar jet array has maximum values of plume length, discharge power, transported charge, and emission intensity at 0.04% HMDSO content.