Chemoenzymatic synthesis of Y-shaped amphiphilic block copolymers and their micellization behavior

BACKGROUND: Y-shaped block copolymers are a type of special star polymer that have received considerable attention due to their unique morphologies and phase behavior. This research is based on the preparation of novel Y-shaped block copolymers using enzymatic ring-opening polymerization (eROP) and atom-transfer radical polymerization (ATRIP), followed by an investigation of their micellization properties. RESULTS: Y-shaped block copolymers consisting of polycaprolactone and poly(glycidyl methacrylate) were synthesized successfully by the combination of eROP and ATRP. NMR, gel permeation chromatography (GPC), Fourier transform infrared and atomic force microscopy analyses confirmed the compositions of the block copolymers. The dispersity obtained from GPC was less than 1.4, which indicated a control of the polymerization. The self-assembly behavior of the Y-shaped block copolymers was investigated in aqueous media. Aggregates of various morphologies (such as spherical micelles, lamellae, worm-like micelles and large compound micelles) were observed. In addition, it was found that both the copolymer composition and concentration in tetrahydrofuran greatly influenced the morphologies of the aggregates. CONCLUSION: The results suggest that the Y-shaped diblock copolymers can be synthesized by simple methods. They have various morphologies, including normal spherical micelles, lamellae, worm-like micelles and large compound micelles. (C) 2009 Society of Chemical Industry