Effect of synthesis temperature of PEO-grafted PU/PS IPNs on surface morphology and in vitro blood compatibility.

When hydrophilic/hydrophobic polymers have a microdomain structure, platelet adhesion and activation are effectively suppressed by prohibition of the excessive assembly of glycoproteins and adenosine triphosphate (ATP) consumption of the platelets on the surface. In this study, poly(ethylene oxide)-grafted hydrophilic polyurethane (PU)/hydrophobic polystyrene (PS) interpenetrating polymer networks (IPNs) were synthesized by varying the synthesis temperature to control the phase separation and the microdomain surface structure, and the effect of the degree of phase separation on the in vitro blood compatibility. The size of the dispersed PS-rich domains in the PU-rich matrix decreased, and the hydrophilicity also decreased as the synthesis temperature of the PS network during the IPN synthesis was decreased, as the phase separation was suppressed during the synthesis. The amount of the adsorbed bovine plasma fibrinogens (BPF) on the PEO-grafted PU/PS IPNs decreased as the synthesis temperature was decreased, and the in vitro adhesion of the platelets was also suppressed on the PEO-grafted PU/PS IPNs prepared at lower temperature. The microdomain structure on the surface affected the adhesion and the activation of the adhered platelets, and the suppression of the phase separation resulted in the decrease of the domain size, which also enhanced the blood compatibility of the PEO-grafted PU/PS IPNs.