In this article, we describe the synthesis and characterization of surface-modified polyamide-6, using poly-dichlorophosphazene and hexachlorocyclophosphazene as coupling agents. The solid surface of this polymer was modified first by the introduction of polar functions (C=O, CH, OR, COOH, COOR, etc.) with a cold plasma technique, then by the treatment of the alcoholic groups on the surface with (NPCl2)(n) and (NPCl2)(3) to graft these substrates through the formation of strong covalent P-O-C bonds, and eventually by the substitution of the residual chlorines on the polyamide-6 surface with different types of fluorinated alcohols (2,2,2-trifluoroethanol and heptadecafluorononanol) and with 4-hydroxyazobenzene. Contact-angle measurements, together with X-ray photoelectron spectroscopy and ultraviolet-visible spectroscopy techniques, support the occurrence of these surface-functionalization reactions. (C) 2008 Wiley Periodicals, Inc.