Through the assembly of polyelectrolyte in aqueous emulsion, we synthesized a series of core shell ionic complex nanoparticles containing anionic polyurethane (PU) and cationic chitosan (CS). The physicochemical properties of PU-CS ionic complex (PU-c-CS) materials were investigated by IR, XPS, DLS, TEM, AFM, general tensile tests, and surface contact angle measurement. It was found that the sizes of the prepared nanoparticles were in the range from 60 to 220 nm, and the films exhibited good mechanical properties. The cell (HUVECs) culture experiments showed that the PU-c-CS films exhibited very low cytotoxicity and supported cell adhesion and growth. Protein (BSA) adsorption was significantly decreased for the PU-c-CS films. Furthermore, the results of prothrombin time (PT) and activated partial thromboplastin time (APTT) indicated that antithrombogenicity of the materials were effectively improved. (C) 2010 Elsevier Ltd. All rights reserved.