Segmented polyurethanes with perfluoropolyether(PFPE) and poly(ethylene oxide) blocks were synthesized y reacting a fluorinated macrodiol(PFPE) and poly(ethylene glycol) (PEG) and methylenebis(phenyleneisocyanate) (MDI) in different ratios in the presence of a solvent. Microphase was studied as a function of fluorine and hard segment content of polyurethanes. The chemical structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and thermal properties of PEO PUs and PFPE/PEO PUs investigated by differential scanning calorimetry(DSC). The relative molar ration of PFPE and PEG and MDI in the polymer played an important role in microphase morphology.