Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5348831 | Applied Surface Science | 2015 | 10 Pages |
Abstract
Atmospheric pressure plasma technology offers attractive perspectives to alter the surface properties of polymers. Within this context, the surface modification of polyethylene (LDPE) by an argon atmospheric pressure plasma jet (APPJ) is profoundly investigated in this work. The influence of two different parameters (applied power and argon flow rate) on the plasma jet characteristics and the LDPE surface properties is examined in detail. In a first step, the APPJ is electrically and visually characterized and visual inspection of the afterglow clearly shows that mainly a variation in argon flow rate can result in a changing afterglow length. A maximum afterglow length is obtained at an argon flow rate of 1-1.25Â slm, while higher gas flows result in turbulence leading to a shorter afterglow. Secondly, the surface modification of LDPE is examined using different analyzing techniques namely water contact angle (WCA) measurements for the wettability, X-ray photoelectron spectroscopy (XPS) for the chemical composition and atomic force microscopy (AFM) for the surface morphology determination. WCA measurements show that by increasing the applied power the wettability of the LDPE increases. Increasing the argon flow rate up to 1.25Â slm gives a decrease in WCA value or in other words an increased wettability. From 1.25Â slm on, an increase in argon flow rate during plasma treatment decreases the LDPE wettability as can be concluded from the increased WCA values. An increased wettability can be explained by the incorporation of oxygen moieties. By increasing the discharge power, the concentrations of all oxygen containing groups such as CO, CO and OCO increase. Increasing the flow rate up to 1.25Â slm results mainly in an increase in OCO groups. However, from a flow rate of 1.25Â slm on, the concentration of all oxygen groups again decreases. Based on these results, the appropriate settings for an efficient plasma treatment can easily be selected.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
A. Van Deynse, P. Cools, C. Leys, N. De Geyter, R. Morent,