RUBBER RUBBER ADHESION WITH CONNECTOR MOLECULES

We consider two rubber blocks A and B in close contact, with some extra A chains (connectors) bound to the surface of the B block and entering freely in the A block. The connectors are assumed not to break, but to slip out by a viscous process when the two blocks are separated. In that model, the adhesion energy has two sources: the thermodynamic work W of Dupre, and the suction work required to pull out the connectors. We show that these two contributions are not simply additive. Our main practical result is to predict the minimum number rho (per unit area) or the minimum length N of the connectors required to enhance significantly the adhesion energy.