Controlled Synthesis of PCL/PVP Copolymer by RAFT Method and Its Hydrophilic Block-Dependent Micellar Behaviors

A range of poly(ε-caprolactone)/poly(N-vinyl-2-pyrrolidone) amphiphilic block copolymers with well-defined hydrophilic chain length were synthesized by the living/controlled reversible addition fragmentation chain transfer polymerization method. The composition and structure of the targeted resultants were characterized with 1H NMR, 13C NMR, FT-IR spectroscopy and gel permeation chromatography. The various block copolymers were successfully employed to fabricate the spherical micelle with core-shell morphological structure. The poly(N-vinyl-2-pyrrolidone) block-dependent characteristics of the copolymeric micelles were investigated by fluorescence spectroscopy dynamic light scattering, and transmission electron microscopy. The solubilization of the hydrophobic ibuprofen as a model drug in the micelle solution was also explored. It was found that the drug loading contents are related to the micellar morphology structure determined by hydrophilic chain length in the copolymer.