In order to investigate the effects of surface roughness, surface wettability and swelling on protein adsorption, polyurethane films were prepared from castor oil (CO) and poly(ethylene glycol)‐3000 (PEG) using one‐shot bulk polymerization. Hexamethylene diisocyanate and 1,4‐butanediol were used as isocyanate and chain extender, respectively. The hydrophilicity of the polyurethane films was adjusted by varying the ratio of CO to PEG. The surface of the polyurethane films was treated using plasma polymerization in the presence of acrylic acid vapour. Therefore, the polyurethane films could be obtained with the same hydrophilicity but with different roughness. The hydrophilicity of untreated and treated polymer films was examined using contact angle measurements. The surface topology of the polymer films was investigated using scanning electron microscopy and atomic force microscopy. Adsorption of bovine serum albumin and bovine serum fibrinogen on treated and untreated polymer films was determined and the performance of the films was compared. After evaluation of all results it is found that surface roughness and swelling are as important as hydrophilicity for protein adsorption in the case of CO/PEG‐based polyurethanes. © 2012 Society of Chemical Industry

Polyethylene glycol (PEG)/castor oil (CO)‐based polyurethanes were prepared by one‐shot bulk polymerization method with the potential for biomedical applications. Hexamethylene diisocyanate and 1,4‐buthane diol were used as diisocyanate component and chain extender, respectively. Polyurethanes were prepared (1) with crosslinker and catalyst, (2) with crosslinker and without catalyst, and (3) without crosslinker and catalyst. The effects of the ratio of CO to PEG, and presence/absence of the crosslinker and catalyst on some physical and surface properties of the polyurethanes were investigated. The glass transition temperatures of prepared polyurethanes are below room temperature. The swelling ratio increased and the water contact angle decreased with increasing amount of PEG in polymer structure. The samples prepared with crosslinker and without catalyst showed the highest swelling ratio. Gas permeability of the samples was measured in a gas permeability system and surface roughness was determined by scanning electron microscope and atomic force microscope. Protein adsorption studies were performed for the samples synthesized without crosslinker and catalyst by using bovine serum albumin and bovine serum fibrinogen. Unexpected results were obtained for the samples which have low contact angles. They exhibited relatively high protein adsorption. POLYM. ENG. SCI., 54:1182–1191, 2014. © 2013 Society of Plastics Engineers