Modulation of adhesion at silicone elastomer-acrylic adhesive interface

To characterize the role of small silica like nanoparticles (MQ resins) in the modulation of adhesion at polydimethyl siloxane (PDMS) elastomers-acrylic adhesive contacts, we have designed systems in which the roles of MQ resins in enhancing interactions at the interface and in increasing viscoelastic dissipations in the elastomer layer could be separated. First, the contact between elastomers with various MQ resin contents and PDMS layers made of densely grafted short chains has been investigated through Johnson-kendall-Roberts (JKR) tests, in order to characterize how the dissipations in the elastomer depend on the resin content. The same elastomers in contact with thin-surface-anchored acrylic layers were then tested through JKR tests to determine the role of enhanced interactions in the modulation of adhesion at the interface due to the resins. In these experiments, the thickness of the acrylic layer was kept small enough so that dissipations in the acrylic adhesive could be neglected. Both Go, the adhesive strength at zero fracture velocity, and G(V), the velocity-dependent fracture toughness, strongly depend on the MQ resin content and on the contact time, suggesting the progressive building of strong interactions between acrylic and elastomer chains.