Plasma-assisted surface alteration of industrial polymers for improved adhesive bonding

The wide-ranging applications of industrial polymers are limited due to their poor surface properties like low free energy, dynamic nature, and ineffective adhesion with self or other polymers. Over the past decade, there has been a continuous growth in the demand of polymers and polymer composites leading to a lot of research efforts on surface modification strategies. Out of the different approaches used for polymer surface modifications, plasma treatment has been found to be one of the most suitable means for increasing the surface energy and adhesion strength through irreversible reactions between dangling bonds on plasma exposed surfaces. This paper reviews the reported literature in the area of plasma modified polymeric surfaces and corresponding changes in their adhesion properties. It also focuses on the retention of plasma modified surface properties of the polymers. The short-term effectiveness of plasma modified surfaces is a major challenge in the field of polymer surface modification. Various aspects of polymer adhesion such as the underlying mechanism of adhesion, the plasma-based surface treatment process, extensive surface characterization studies, and adhesion measurement techniques are briefly explained for a proper understanding of the area. The paper also considers the literature reported for time-dependent change of surface properties and the adhesion performance of plasma modified polymers. Despite the several efforts for the surface modification of polymers, the long-term storage of modified surface properties is still a challenge, and further research is warranted in this area to span the polymer applications domain to industrial needs.