Mono- and diethyleneglycol functionalized polyglutamates (PEG_nG) were synthesized by the ring-opening polymerization of N-carboxyanhydride (NCA) directly. Firstly, EG-L-glutamates were synthesized by the reaction of glutamic acid and ethylene glycol monomethyl ether or di(ethylene glycol) monomethyl ether. And then, EG-L-glutamate-N-carboxyanhydride was prepared by glutamate and triphosgen. The structure and basic properties were characterized by IR, ¹H NMR, GPC and water affinity measurements. The results showed that the hydrophilicity was increased effectively, which depends on the number of EG groups on the side chain. Poly[α-2-(2-methoxyethoxy)-ethyl-γ-glutamate] (PEG₂G) was found to be water soluble. The TEM result showed that PEG₂G self-assembled into micelles in water.

Key words: poly(amino acid), glutamate, ring-opening polymerization, micelle