Synthesis, Self-Assembly, and Hydrolytic Degradation of PEG-Based Biodegradable Block Copolymers

In this study, PEG-based amphiphilic biodegradable block copolymers were synthesized to investigate the effect of block composition on self-assembly and hydrolytic degradation. PEG-b-PeDL diblock copolymers were prepared by ring-opening polymerization of ε-decalactone using mPEG as a macroinitiator, which was further chain-extended with L-lactide to obtain PEG-b-PeDL-b-PLLA triblock copolymers. The resulting copolymers were analyzed by ¹H NMR spectroscopy and GPC. Their micellar assemblies in aqueous media were characterized by DLS. Under alkaline conditions (pH 11), PEG-b-PeDL showed minimal size variation, whereas PEG-b-PeDL-b-PLLA exhibited time-dependent changes in hydrodynamic diameter, suggesting hydrolytic degradation of the polyester blocks. These results indicate that block composition plays an important role in the assembly and degradation behavior of PEG-based biodegradable copolymers.