The European Physical Journal Applied Physics

Research Article

Polystyrene thin films treatment under DC pulsed discharges conditions in nitrogen

F. Clémenta1, B. Helda1, N. Soulema1 and N. Spyroua2

Laboratoire d'Électronique, des Gaz et des Plasmas, Université de Pau, 64000 Pau, France

Laboratoire des Matériaux de l'Électrotechnique, Université de Patras, 26500 Rio-Patras, Greece

Abstract

A systematic parameters study is performed in a DC pulsed glow discharge in nitrogen in order to improve the wettability of thin polystyrene layers. The experimental parameters considered are the pressure P, the interelectrode voltage V, the frequency ν of the pulsed power supply and the treatment time t t. The wettability is characterized by the contact angle technic. The $(\Theta_{\rm i} - \Theta_{\rm f})/\Theta_{\rm i} = \Delta \Theta / \Theta_{\rm i}$ ratio is measured, where $\Theta_{\rm i}$ and $\Theta_{\rm f}$ are respectively the initial and final contact angles. In the first part of the paper, the variations of $\Delta \Theta / \Theta_{\rm i}$ as a function of the electrical energy E are investigated, the variations of E being obtained by modifying the parameters V, ν and/or t t. In the second part, the specific energy ε and the economical criterion γ are introduced to deduce the best running conditions through a chemical engineering approach. Taking into account the weak duty factor of the power supply (1% ), it is shown that the polymer surface is treated with a minimum of energy.

(Received July 24 2000)

(Revised November 10 2000)

(Accepted November 24 2000)

(Online publication January 15 2001)

PACS:

  • 52.75.-d – Plasma devices and applications;
  • 81.65.-b – Surface treatments;
  • 82.65.Pa – Surface-enhanced molecular states and other gas-surface interactions
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