Typical polymeric substrates often employed for the medical devices of the present invention include thermoplastic polyurethanes (TPU), polyesters such as polyethylene terephthalate (PET), nylon polymers such as nylon-11 and nylon-1 2, block copolymers of polyether and polyester polymers (for example various HYTREL??? block copolymers, available from DuPONT), block copolymers of polyether polymers