Polymer-polymer adhesion with mobile promoters: Connector areal density dependence

The adhesion between two immiscible polymers stitched together via mobile promoters is studied with large scale molecular simulations employing a coarse-grained bead-spring model. An adhesion model is presented that enables both connector molecular slipping out viscously and bulk dissipation in two dissimilar glassy polymers, in which one is dense melt and another is loose. The contributions to the separation work from thermodynamics and chain suction are studied in dependence of the connector areal density, at constant temperature, and at fixed basic molecular parameters. It is shown that high connector coverage, but below saturation areal density, can enhance the adhesion toughness and interfacial strength. Bulk dissipation is not considerable with low connector areal density in mushroom regime, while becomes more evident in the loose block when the coverage density is increased up to overlapping brush regime. With increasing connector length, both bulk melts are enhanced by the segments of connector chains that penetrated in. The results provide insight into the structure evolution of adhesion interface coupled with promoter molecular, which are useful for future developments of continuum cohesive models for fracture of polymer- polymer interfaces.