Although it has ho widely accepted that both block and graft copolymerwill form microphase separation morphology

only detailed morphological knowledge of block copolymers has been reported so far. In choosing an amphiphilicgraft copolymer

namely polystyrene-g-poly(ethylene oxide)(PS-g-PEO) as amodel copolymer

the microphase morphological feature of graft copolymer wasstudied systelnatically for the first bine by means of thensmission electron microscopy.It Was discovered that PS-g-PEO may readily undergo microphase separation and the shape and size of domains depand on the composition and PEO side chain length of the graft copolymer. Both the similarity and difference of the microphase structure between block and graft copolymer were also discussed.