A Y-shaped diblock copolymer with a functional block poly(glycidyl methacrylate) was synthesized via the combination of enzymatic ring-opening polymerization (eROP) and atom transfer radical polymerization (ATRP). The synthetic procedure involved eROP of epsilon-caprolactone (epsilon-CL) in the presence of biocatalyst Novozyme 435 and initiator 1H,1H,2H,2H-perfluoro-1-octaoxy, subsequently the resulting poly(epsilon-caprolactone) (PCL) was converted to a macroinitiator by esterification of it with 2,2-dichloro acetyl chloride, and finally the ATRP of glycidyl methacrylate (GMA) was conducted at 60 degrees C with CuCl/2,2'-bipyridine as the catalyst system. By this process, we obtained copolymers with a controlled molecular weight and a low polydispersity. The structure and composition of the obtained polymers were characterized by H NMR, GPC, and IR. Linear first-order kinetics, linearly increased molecular weight with conversion, and low polydispersities were observed for the ATRP of GMA. The thermal properties of the copolymer were characterized by differential scanning calorimetry. The self-assembly behavior of the Y-shaped block copolymer was also investigated in different solvents and at different concentrations. The aggregates of various morphologies (spheres, worm-like patterns, nanowell patterns, and dendritic patterns) were observed. It was found that solvents remarkably influenced the morphologies of the films spin-coated from the corresponding solutions. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5509-5526, 2009