The polymerization of trimethylene carbonate (TMC) in the presence of HCl center dot Et2O via activated monomer mechanism was performed to synthesize linear and star-shaped block copolymers composed of polyethyleneglycol (PEG) and poly(trimethylene carbonate) (PTMC). The obtained PTMCs bad molecular weights close to the theoretical values calculated from the TMC to PEG molar ratios and exibited monomodal GPC curves. We successfully prepared PEG and PTMC linear and star-shaped block copolymers by activated monomer mechanism. The characterization for formation of micelle of block copolymers in an aqueous phase was carried out by using NMR, dynamic light scattering (DLS), AFM and fluorescence techniques (FL). The block copolymers gave micelles with a critical micelle concentration (CMC) ranging 1.88 x 10(-2) -3.09 x 10(-3) mg/mL depended on the molecular shape of block copolymers. The diameters of micelles, measured by DLS, were 100-250 nm. Most micelles exhibited a spherical shape in AFM. (C) 2007 Elsevier B.V. All rights reserved.