Synthesis and Self-Assembly Behavior of Amphiphilic Polypeptide-Based Brush-Coil Block Copolymers

Synthesis and self-assembly behavior of a novel amphiphilic brush-coil block copolymer bearing hydrophilic poly(ethylene glycol) segment and hydrophobic polypeptide brush segment were presented in this work. The poly(gamma-benzyl-L-glutamate) (PBLG) brush is synthesized through "grafting from" strategy by ring-opening polymerization of gamma-benzyl-L-glutamate-N-carboxyanhydride (BLG-NCA) initiated by the flanking terminal primary amino group of macroinitiator. The copolymers were characterized by H-1 NMR, gel permeation chromatography, Fourier transform infrared, circular dichroism spectrum, and differential scanning calorimetry. The self-assembly behavior of the brush-coil block copolymers in aqueous solution was investigated by means of transmission electron microscopy, scanning electron microscopy, atomic force microscopy, and laser light scattering. Spherical micelles were observed when the length of PBLG brush is shorter. The aggregate morphology transforms to spindle-like micelles and then to rod-like micelles, as the length of polypeptide brush increases. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5967-5978, 2009