Surface Dynamics vs. Adhesion in Oxygen Plasma Treated Polyolefins

Abstract

Polyethylene (PE) and polypropylene (PP) were oxygen plasma treated and aged in carefully reproducible conditions. The effect of aging on the surface chemistry, wettability and adhesion were studied using a combination of techniques: contact angle measurements, XPS, SSIMS, adhesion tests (shear and pull). PE was found to be relatively insensitive to aging both in terms of wettability and adhesion, due to crosslinking during plasma treatment, which is likely to reduce macromolecular mobility within the surface layer. In the case of PP, dramatic decreases of wettability occur with time, due to macromolecular motions leading to minimization of oxygen-containing functions at the surface. This behavior was shown to affect the adhesion performance of treated PP.