Regular Article

Impact of an atmospheric argon plasma jet on a dielectric surface and desorption of organic molecules^*

LPGP, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay, 91405 Orsay Cedex, France

^a e-mail: stephane.pasquiers@u-psud.fr

Received: 1 December 2015
Revised: 9 March 2016
Accepted: 26 April 2016
Published online: 8 August 2016

Abstract

The propagation of a DC-pulsed argon plasma jet through the surrounding ambient air, and its interaction with an ungrounded glass plate placed on the jet trajectory, was studied by means of fast imaging. The surface plays an important role in the spatio-temporal characteristics of the plasma. Indeed, for an argon jet propagating perpendicularly to the surface, the plasma jet structure changes from filamentary to diffuse when the distance between the nozzle of the capillary tube and the surface is short (≤10 mm). Changing the angle between the capillary tube and the glass plate, and varying the gas flow rate strongly affects the spatial extension of the plasma that develops on the surface. This surface plasma propagates while the plasma in the argon jet is maintained with the same luminous intensity. Finally, this plasma jet shows interesting characteristics for desorption of low volatile organic molecules such as bibenzyl. A maximum removal of bibenzyl is located at the intersection area between the jet axis and the glass surface, and some of the initially deposited molecules are found intact in gas phase.