Wetting Measurements for Identification of Specific Functional Groups Responsible for Adhesion

The relationship between adhesion and surface energy is well established for systems where specific chemical interactions are unlikely, such as pressure sensitive adhesives. However, the relationship of wetting to adhesion in chemically reactive systems is not well understood. This work used atmospheric pressure plasma treatment in air of high density polyethylene to obtain surfaces with a range of electron donor and acceptor character prior to bonding with an amine cured epoxy. Adhesion correlated strongly with the electron donating character of surface energy, and the likely functional groups responsible for this adhesion were amines created by the plasma treatment process. These results indicate that wetting measurements may be useful in detecting the specific chemical interactions important to adhesion in reactive systems.