Plasma etching of a polymeric dielectric material such as polyurethane results in volatile byproducts that are deposited onto the surface of an inert substrate. The surface treatment increases adhesiveness so that the surface of the inert material may be bonded to another material. Portions of a medical device comprising an inert substrate such as a fluoropolymer may therefore be securely affixed to other portions of the medical device formed of polymeric, metallic, or ceramic materials.