A series of poly(ethylene glycol) (PEG)-4

4′-diphenylmethanediisocyanate (MDI)-poly(dimethyl-siloxane) (PDMS) multiblock copolymers were synthesized by employing two step growth polymerization technique.Surface phase separation behavior of these multiblock copolymer coatings was studied by atomic force microscopy (AFM) with ultra-light tapping mode.The results showed that nanoscopically well-organized phase-separated surfaces consisting of hydrophilic domains of PEG and MDI segments and hydrophobic domains of PDMS segments were clearly observed even the concentration of PDMS segments in the copolymer was more than 50 wt%

and the microphase separation pattern depended on the annealing

weight fraction of hydrophilic domains or hydrophobic domains and composition of hydrophilic domains.Formation mechanism of surface phase separation was also discussed.