LDPE Surface Modifications Induced by Atmospheric Plasma Torches with Linear and Showerhead Configurations

TL;DR

This study compares atmospheric plasma torch configurations to modify LDPE surfaces, enhancing their properties for better coating adhesion and barrier performance through chemical and morphological changes.

Contribution

It provides a comparative analysis of showerhead and linear plasma torches on LDPE, detailing how different parameters influence surface modifications.

Findings

Showerhead and linear torches produce distinct surface modifications.

Treatment parameters significantly affect etching and roughening rates.

Chemical composition of post-discharges correlates with surface functionalization.

Abstract

Low density polyethylene (LDPE) surfaces have been plasma modified to improve their nanostructural and wettability properties. These modifications can significantly improve the deposition of subsequent layers such as films with specific barrier properties. For this purpose, we compare the treatments induced by two atmospheric plasma torches with different configurations (showerhead vs. linear). The modifications of LDPE films in terms of chemical surface composition and surface morphology are evidenced by X-ray photoelectron spectro-scopy, water contact angles measurements, and atomic force microscopy. A comparison between the two post-discharge treatments is achieved for several torch-to-substrate distances (gaps), treatment times, and oxygen flow rates in terms of etching rate, roughening rate, diffusion of oxygen into the subsur-face and hydrophilicity. By correlating these results with the chemical composition of the post-discharges, we identify and compare the 'species which are responsible for the chemical surface functionalization, the surface roughening, and etching.