Polystyrene thin films treatment under DC pulsed discharges conditions in nitrogen
Résumé
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 tt. The wettability is characterized by the contact angle technic. The (Θi-Θf)/Θi = ΔΘ/Θi ratio is measured, where Θi and Θf are respectively the initial and final contact angles. In the first part of the paper, the variations of ΔΘ/Θi as a function of the electrical energy E are investigated, the variations of E being obtained by modifying the parameters V, ν and/or tt. 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.