A model multiblock copolymer based on (Poly dimethylsiloxane) (PDMS),-4, 4'-diphenylmethanediisocyanate (MDI)-(poly ethylene glycol) (PEG) was synthesized by employing two step growth polymerization technique. The effect of annealing on microphase separation of the copolymer surface and bulk, surface composition, hydrogen-bonding and some properties was investigated by AFM, SAXS, XPS, FTIR, contact angle measurement, and protein adsorption experiment, respectively. It was found that increasing the annealing temperature availed formation of microphase separation and surface enrichment of PDMS, which was accompanied by increase in average interdomain spacing, long period, and the crystallizing degree in the hard domains. But the best microphase separated structure seemed to occur at the annealing temperature of 140 degrees C; exorbitant annealing temperature might demolish the ordered structure. The annealing temperature dependence of microphase separation was further confirmed by the changes in urea hydrogen-bonding and melting points characterized by FTIR and DSC, respectively. Protein adsorption experiments revealed that all annealed copolymer films possessed the low protein adsorption. (c) 2006 Wiley Periodicals, Inc.