Surface modification of polyethylene using argon and argon/methane DBD atmospheric pressure plasma jet

Abstract

This article investigates the surface modification of polyethylene (PE) using an atmospheric pressure plasma jet of the DBD type (APPJ) maintained with pure argon (Ar) and with a premixed gas containing 90% argon and 10% of CH4. First and for both plasma jets, the jet length and the optical emissions coming from the plasma species were studied in terms of flow rate and applied voltage. Comparing to Ar, it has been shown that when the premixed gas is used, the jet length gets smaller, the transition point from laminar to turbulent regime was shifted to a low flow rate, and the emission of CH, H2 and C2 appeared, while O and N2 emission coming from ambient air was quenching. The PE surface treatment in both laminar and turbulent regime has been evaluated using water contact angle (WCA) measurement and attenuated total reflection (ATR). The obtained results showed that the hydrophilicity of PE has been improved in both plasma jets due to oxygen group (C=O) incorporation, but Ar plasma jet was observed to induce surface degradation compared to Ar/CH4 plasma due to the higher excited species.