Fluorinated siloxane-containing waterborne polyurethaneureas with excellent hemocompatibility, waterproof and mechanical properties

Two series of polyurethaneurea (PUU) aqueous dispersions consisting of fluorinated siloxane segments were prepared from a high-molecular-weight (M_n = 8361) α,ω-dihydroxypoly[(3,3,3-trifluoropropyl)methylsiloxane] (PTFPMS), dimethylolpropionic acid, isophorone diisocyanate and ethylenediamine, with poly (tetramethylene oxide) and polycarbonate polyols as soft segments, respectively. These anionic aqueous dispersions were stable at the ambient temperature for more than 6 months, with particle sizes ranging from 45 to 98 nm. Both series of PUU films showed the excellent waterproof properties, i.e. the decrease in water absorption and surface energy upon the incorporation of PTFPMS segments. The phase mixing increased in the fluorinated siloxane-containing polyether-based PUUs and the phase separation increased first then decreased in the fluorinated siloxane-containing polycarbonate-based PUUs, with increasing PTFPMS content. All the PTFPMS-modified PUU films showed excellent mechanical properties. The polycarbonate-based PUU film consisting of 5 wt.% PTFPMS had a tensile strength of 60.7 MPa and a breaking elongation of 632%, owing to the increase in the ordered hydrogen bonding degree and the microphase-separation degree between the hard and soft segments in the system. In vitro hemolysis and dynamic clotting time measurements indicated that the thromboresistance was enhanced markedly with increasing PTFPMS content for both series of PUUs, which could be ascribed to the synergistic effect between the carboxylate groups and the PTFPMS segments migrating onto the surfaces of the films.