Study on Self-assembly of Poly(ethylene glycol)-block-poly(γ-benzyl L-glutamate)-graft-poly(ethylene glycol)Copolymer and Poly(γ-benzyl L-glutamate)-block-poly(ethylene glycol) Copolymer in Ethanol

摘要

Poly(ethylene glycol)-block-poly(γ-benzyl L-glutamate)-graft-poly(ethylene glycol) (PEG-b-PBLG-g-PEG) copolymer was synthe-sized by the ester exchange reaction of poly(γ-benzyl L-glutamate)-block-poly(ethylene glycol) (PBLG-block-PEG) copolymer withPEG chain, and PBLG-block-PEG copolymer was prepared by a standard N-carboxyl-y-benzyl-L-glutamate anhydride (NCA)method. Nuclear magnetic resonance (NMR) spectroscopy was used to confirm the components of PBLG-block-PEG and PEG-b-PBLG-g-PEG. The self-association behaviors of PBLG-block-PEG and PEG-b-PBLG-g-PEG in ethanol were investigated bytransmission electron microscopy (TEM), dynamic laser scattering (DLS), and viscometry. The experimental results revealed thatthe different molecular structures could exert marked effects on the self-assembly behaviors of PBLG-block-PEG and PEG-b-PBLG-g-PEG in ethanol. PBLG-block-PEG and PEG-b-PBLG-g-PEG could self-assemble to form polymeric micelles with a core-shellstructure in the shapes of plump spherical and regular rice-like, respectively. Effects of the introduction of PBLG homopolymer onthe average particle diameter of the micelles of PBLG-block-PEG and PEG-b-PBLG-g-PEG and influence of testing temperature onthe critical micelle concentration of different copolymers were studied.