The design and synthesis of new linear-dendritic diblock copolymers with a linear PEO block and a dendrimeric PAMAM block are described. Two series with PEO molecular weights of 2000 and 5000 were synthesized. DSC results on the effect of diblock composition on the microphase segregation behavior of the diblocks are reported. Glass transition temperatures of the diblocks depend on the end group functionality of the dendrimer. The aqueous solution behavior of the hybrid copolymers at 30 degrees C studied using intrinsic viscosity and GPC techniques is influenced by the length of the PEO block and the end group functionality of the dendrimer. The intrinsic viscosity trends exhibited by the diblocks with the shorter PEO chain length did not deviate greatly from that of linear polymers, and those exhibited by the diblocks with the longer PEO chain length indicate the formation of unimolecular micelles.