Polystyrene thin films treatment under DC pulsed discharge in nitrogen: effect of sample placement and glow duration on the wettability

¹ Laboratoire d'Électronique, des Gaz et des Plasmas, IPREM – FR CNRS 2606, EA 750, Université de Pau et des Pays de l'Adour, UFR Sciences, BP 1155, 64013 Pau Cedex, France
² Electrotechnic Materials Laboratory, Electrical and Computer Engineering Department, University of Patras, 26500 Patras-Rio, Greece

Corresponding author: bernard.held@univ-pau.fr

Received: 7 April 2004
Revised: 24 August 2004
Accepted: 2 September 2004
Published online: 23 November 2004

Abstract

This paper is devoted to atactic polystyrene (aPS) thin films treatment under DC pulsed discharge in nitrogen. The experiments were performed using a symmetrical plane-to-plane of electrodes configuration in order to improve the treatment homogeneity and also to compare the treatment efficiency when the aPS is on the cathode or on the anode. During these experiments, the pressure and the electrical conditions were maintained unchanged. The experimental results were compared for the two positions of samples, when the gap length and the afterglow duration time were varied. It appears that the treatment depends on the sample position and an interpretation is proposed. The physical conditions and the reaction processes in the plasma bulk and on the aPS surface were analysed in order to understand their influence on the surface treatment. The importance of metastables is pointed out and it is deduced that these long-life excited states are firstly produced near the anode and fill the gap following the evolution and distribution of the electron current density.