Two new polyamidoamines derived from piperazine (Pip)/cyclohexylamine (CHA) and N,N'-methylene bisacrylamide (MBA) were synthesized and subsequently copolymerized with N-vinylpyrrolidone (NVP) under suitable reaction conditions to yield the respective copolymers (Pip-MBA-NVP and CHA-MBA-NVP). The synthesized materials were characterized by spectroscopic techniques. The material surface characteristics were checked by contact angle measurement, and the data established the relative hydrophilic characteristics of the synthesized copolymers with respect to the control poly(N-vinylpyrrolidone). A thrombus-formation study indicated less (<1.2 mg) clot formation on the heparinized material surfaces within a 30-min contact time with the acid citrate dextrose human blood. The percentage of hemolysis of the blood by the materials was also less than 5%. (C) 2003 Wiley Periodicals, Inc.