Enhancing adhesion of fluorinated ethylene propylene through atmospheric pressure nitrogen plasma treatment: a comprehensive adhesive selection approach for optimal peel strength characterization

Fluoropolymer films were treated by atmospheric pressure nitrogen plasma in a roll-to-roll configuration. This treatment aimed to modify the surface properties of the fluoropolymer and assess its adhesion with commercial silicone, rubber, and acrylic adhesive tapes. Fluoropolymer films and adhesives were characterized using contact angle measurements, Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS), and T-peel tests. The plasma treatment resulted in increased wettability of the films, defluorination of the fluoropolymer surface, the introduction of oxygen- and nitrogen-containing functional groups on the surface, and a reduction in surface roughness. Peel strength increased at different levels, depending on the treatment speed and adhesive employed. Silicone adhesives did not present a significant increase on plasma-treated fluoropolymer films; however, they presented the higher peel strength against the untreated substrate. Acrylic adhesives are sensitive to fluoropolymer surface chemistry and can be used to evaluate different plasma treatments, while the highest adhesion was obtained with rubber adhesives. The results presented herein provide information about the appropriate selection of the type of adhesive for a specific application, as well as the evaluation of surface modifications by T-peel test.