Roles of molecular architecture and end-group functionality on the surface properties of branched polymers

The effects of molecular architecture on the surface properties of polyetherimide polymer films were investigated. For polymers ranging in structure from hyperbranched to completely linear, it was found that the presence of branches limits the mobility of polymeric segments, which inhibited the migration of interior end-groups to the film surfaces. As a result, the surface energy of randomly branched polymers scales with the number of terminal segments which are located at the periphery of molecules. For a series of branched polymers with compositionally identical end-groups and repeat units, the surface properties were independent of molecular architecture. The results of this study also indicate that the surface properties of hyperbranched polymers strongly depend on the functionality of end-groups.