Adhesion energy between metal films and polymers obtained by studying buckling induced by hydrogen Original Research Article

Hydrogen absorption in niobium films on polycarbonate (PC) gives rise to large compressive in plane stresses which finally lead to a delamination of the metal. Delamination occurs via straight and wrinkled buckles. By doping the Nb-film electrochemically with hydrogen, the increasing stresses are measured by determining the curvature of the PC-substrate. The critical stress for buckling is measured for 50-, 100- and 200-nm thick Nb-films which were covered on both sides with a 10-nm thick Palladium film. It can be shown that the critical stresses are required to overcome the adhesion between Pd and PC. From a simple energy balance between the adhesion energy and the released elastic energy, a value of about 1 J/m2 for the adhesion energy is calculated. The new concept of measuring adhesion can be applied to all combinations of two materials, if the dissolution of substances in one of them causes compressive stresses.