An implantable material has at least one external surface grafted with a film including carboxylate and sulfonate functions wherein the film is simultaneously synthesized and grafted directly on the external surface by radical reaction of a source of carboxylate functions, the source being either polymerizable or chemisorbable and polymerizable and a source of sulfonate functions, the source being either polymerizable or chemisorbable and polymerizable. A process for simultaneously synthesizing and grafting a film directly onto at least one external surface of an implantable material, and the use of a grafted implantable material for the manufacture of an antiproliferative and/or antibacterial implantable medical device are also described.