Surface properties and platelet reactivity of segmented poly(etherurethanes) and poly(etherurethaneureas)

Segmented poly(etherurethanes) (SPUs) and segmented poly(etherurethaneureas) (SPUUs) with various hard and soft segment components were prepared. The surface characterization of SPUs and SPUUs in the air-equilibrated state and in the hydrated-state was carried out by means of X-ray photoelectron spectroscopic (XPS) and dynamic contact angle measurements. XPS revealed that in the air-equilibrated state, lower surface free energy components were enriched at the air-solid interface, whereas in the hydrated-state higher surface free energy components were enriched at the water-solid interface. The change in environment from air to water induced the surface reorganization in order to minimize interfacial free energy. The large contact angle hysteresis was observed for SPUs and SPUUs. This hysteresis can be mainly ascribed to the surface reorganization process. Platelet adhesion tests on SPU and SPUU surfaces indicated that the existence of surface microphase separated structure played an important role in the attainment of blood compatibility.