Adhesive properties of silicone polymers on some typical opto-electronic substrates: influence of the network density

This study examines the influence of the microstructural properties of a silicone polymer network and the surface properties of opto-electronic substrates on the adhesive properties. We highlighted the influence of the silicon network microstructure on the type of break between the silicon polymer and the substrate: from an adhesive to a cohesive break when the cross-links density decreases with some formulations that give rise to some typical behaviours. Finite element analysis was used to explain these behaviours. We also showed that the quality of the interface evolves in function of the viscosity of the silicon polymer before cross-linking and the number of Si-H functions it has. A better adhesion on silicon polymer/silica than on silicon polymer/lnP is ascribed to the chemical composition surface being similar to the chemical structure of the silicon polymers and to more favourable surface energies. (C) 2003 Elsevier Ltd. All rights reserved.