Adhesion at polymer-solid interfaces: Influence of sticker groups on structure, chain connectivity and strength

The influence of sticker groups (COOH) on the adhesion energy (G(IC)) of a model carboxylated polybutadiene-amine terminated silane modified aluminum (cPBD-AlS) interface was examined using a T-peel test. An optimal COOH concentration of around 0.5 mol% was observed. At this concentration the interface possessed a maximum peel energy of 600 J/m(2) which is approximately equal to the cohesive peel energy of PBD. The adhesion strength of the interface increased as the interaction parameter (chi(P-S)) between COOH and the solid substrate increased. Additionally, G(IC) was strongly dependent on the annealing time, resulting from slow surface reorganization processes. The interface structure was explored using the self-consistent held lattice model (SCFLM) developed by Theodorou. An interphase region adjacent to the solid substrate was found as a consequence of a gradient in chain connectivity and a strong sticker group segregation near the solid surface. The modeling study provided information about how the interphase structure changed with phi and chi(P-S), explaining the experimental results well.