Hyperbranched polyesters (HPs) with a variable content of benzoyl terminal groups were synthesized through the chemical modification of the HPs' cores by substituting a controlled fraction of the terminal hydroxyl groups with benzoyl chloride. The resulting hyperbranched polymers that were modified by benzoyl groups (HPs-B) were characterized by H-1 NMR, FTIR, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). Research results revealed that self-assembled structures could be formed in selected solvents (acetone/n-hexane). It was found that the morphologies of self-assembled structures could be adjusted by controlling the content of outside benzoyl terminal groups in the hyperbranched polymers, the volume ratio of acetone with n-hexane, and the concentration of the hyperbranched polymers with benzoyl terminal arms. (c) 2005 Wiley Periodicals, Inc.