A series of block copoly(polyethylene glycol-styrene) was prepared via the synthetic macromonomer and macroinitiator methods, respectively. The polystyrene (PS) percentage and its block repeat unit were 34-89% and 9.2-2.1, as determined by gel permeation chromatography (GPC) and element analysis (EA), respectively. Furthermore, the structure was identified by Fourier transform infrared spectrophotometer (FTIR). Differential scanning calorimetry (DSC) and transmitted electron microscopy (TEM) were employed to observe the microphase separation morphology. Experimental results indicated that rod and vesicle PEG were distributed within the PS phase. Finally, microphase morphology and molecule simulation were combined to examine the correlation between composition and phase. (C) 2002 Elsevier Science B.V. All rights reserved.