Tailoring the Surface Properties of Silicone Elastomers to Improve Adhesion of Epoxy Topcoat

Two modification routes have been applied to control the surface properties of spin-coated and screen-printed poly(dimethylsiloxane) (PDMS) layers and to improve their adhesion to a photopatternable epoxy resin topcoat. The first route is based on the optimization of low-pressure oxygen and ammonia plasma treatments to generate acidic or basic reactive surface groups capable of forming covalent bonds with the epoxy groups of the topcoat. The main disadvantage of these fast and practicable processes is the instability of the modification effects. Therefore, the plasma-activated PDMS surfaces were used for subsequent 'grafting to' procedures with reactive polymers. The functional surface groups generated by oxygen or ammonia plasma treatments of PDMS (SiOH, OH, COOH and NH2) were used as anchors to graft epoxy group containing homopolymers and copolymers as well as maleic anhydride copolymers. All of grafted materials provided thin barrier layers that prevented the hydrophobic recovery of the modified PDMS ...