Effective and frequently used surface modification methods for polymeric materials are plasma treatment methods. They allow the selective modification of surface properties such as, for example, biocompatibility, surface roughness, surface free energy or degree of wettability, while other material characteristics remain unchanged. Changes in surface characteristics, due to the use of plasma generated, for example, by an external field at 13.56 MHz (Radio Frequency Chemical Vapour Deposition technique), can result from the formation of new chemical structures in the surface layer of the material. In this study, plasmochemical modification of biomedical polymers, a semi-crystalline, thermoplastic polymer known as polyetheretherketone PEEK and polyurethane PU were carried out to improve the surface properties of these materials. The surfaces of the polymers were modified by ion etching in low - temperature plasma in an Ar, N$_{2}$, O$_{2}$ atmosphere for 900 s. The modified biopolymers were characterised in terms of chemical composition, surface morphology as well as surface free energy measurements. Changes in surface topography and an increase in roughness were observed for both materials modified in N$_{2}$ plasma. The largest increase in the polar component of the surface energy was observed for PEEK modified in oxygen plasma, for PU in Ar atmosphere.
