Segmented poly(etherurethaneureas) (SPUUs) with hydrophilic and hydrophobic polyether components were prepared. The surface chemical composition of SPUUs in various environments was investigated by means of X-ray photoelectron spectroscopic and dynamic contact angle measurements. These measurements revealed that in a hydrated state, the higher surface free energy component is enriched on the surface of the SPUU in order to minimize the interfacial free energy between water and the solid surface. The surface molecular mobility showed a strong correlation with bulk molecular motion. Platelet adhesion tests and dynamic contact angle measurements after adsorption of bovine serum albumin revealed that the surface of SPUUs with hydrophilic soft segments has a non-adhesive nature. The platelet reactivity of hydrophobic SPUUs is influenced by microphase separation at the surface.