Insight into the remaining high surface energy of atmospheric DBD plasma-treated polyethylene web after three months’ aging

Abstract

In this paper, we report the modification of polyethylene (45 μm in thickness) webs through a roll-to-roll dielectric barrier discharge plasma treatment in an open atmospheric environment. Our work differs from the normal adopted corona discharge treatment at an atmospheric pressure, in that three monomers: allylamine, acrylic acid, and ethanol, are inlet into the discharge zone by argon (Ar) carrier gas. As a comparison, Ar plasma treatment is also carried out. We focus on the aging properties of treated plastics in the open air. It is found that the modified webs can retain the surface energy as high as 50.0±1 mN m −1 for more than three months. After characterization of the as-prepared and aged samples by the surface roughness, the wettability, and the chemical structure, the mechanism of retaining high surface energy is then presumed. We think that the initial high surface energy just after plasma treatment is correlated to the grafted functional groups, while the over 50.0 mN m −1 remaining surface energy after three month aging is due to the stable concentrations of oxygen-contained and nitrogencontained groups by post-reaction on the surfaces.

Pre-grafted Group on PE Surface by DBD Plasma and Its Influence on the Oxygen Permeation with Coated SiOx

“…For the polymeric surface modification, an atmospheric pressure roll-to-roll DBD setup was utilized, which has been described in other papers [ 36 , 54 ]. Here we give a brief introduction.…”

“…Note that only the DBD modified side of the PE web was deposited with SiOx. Because the monomer modified sample can remain at the high surface energy for over 3 months [ 36 ], we did not intentionally fix the period between the plasma treatment and the SiOx deposition. Normally the treated samples were put into the chamber for PECVD SiOx after 2–3 h.…”

“…Annick Van Deynse et al [ 35 ] added 2% of ethanol to the nitrogen plasma in vacuum-based DBD discharge and obtained a stable WCA at 7.5 ± 1.4° even after being stored in ambient air at a temperature of 20 °C, the relative humidity of 50% for a period of 45 days. Recently, our group also reported [ 36 ] that the treated PE was stable at a high surface energy after 3-month aging if they were treated by Ar+acrylic acid, Ar+allylamine and Ar+ethanol in an atmospheric-based roll-to-roll DBD discharge.…”

“…Following our previous work [ 36 ], in this paper we report on the deposition of SiOx coating on monomer-modified PE samples. Three monomers with different polar groups i.e., -NH 2 , -COOH, -OH, were utilized to modify the PE surface.…”

Influenceof Vinyl Acetate Content on the Surface Hydrophobic Recovery of Ethylene Vinyl Acetate Copolymer after Plasma Modification

“…Plasma modification is an effective way to improve the surface hydrophilicity of polymer materials . The modified thickness is usually confined to the top several tens nanometers and would not affect the bulk properties . Generally, the polymer surface would be hydrophilic state immediately after plasma modification, but the surface would return to hydrophobic state after a few hours or days, which is called hydrophobic recovery .…”