Synthesis and self-assembly of amphiphilic brush-dendritic-linear poly[poly(ethylene glycol) methyl ether methacrylate]-b- polyamidoamine-b-poly(ε-caprolactone) copolymers

A series of novel amphiphilic brush-dendritic-linear poly[poly(ethylene glycol) methyl ether methacrylate]-b-polyamidoamine-b-poly(e-caprolactone) copolymers (PPEGMEMA-b-Dm-b-PCL) (m = 1, 2, and 3: the generation number of dendron) were synthesized by the combination techniques of click chemistry, atom transfer radical polymerization (ATRP), and ring-opening polymerization (ROP). The brush-dendritic copolymers bearing hydrophilic brush PPEGMEMA and hydrophobic dendron polyamidoamine protected by the tert-butoxycarbonyl (Boc) groups [Dm-(Boc)?2m (m = 1, 2, and 3)] were for the first time prepared by ATRP of poly(ethylene glycol) methyl ether methacrylate monomer (PEGMEMA) initiated with the dendron initiator, which was prepared from 2'-azidoethyl-2-bromoisobutyrate (AEBIB) and Dm-(Boc)?2m terminated with a clickable alkyne by click chemistry. Then, the brush-dendritic copolymers with primary amine groups (PPEGMEMA-b-Dm) were obtained from the removal of the protected Boc groups of the brush-dendritic copolymers in the presence of trifluoroacetic acid. The brush-dendritic-linear PPEGMEMA-b-Dm-b-PCL copolymers were synthesized from ROP of e-caprolactone monomer using PPEGMEMA-b-Dm as the macroinitiators and stannous octoate as catalyst in toluene at 130 degrees C. To the best of our knowledge, this is the first report that integrates hydrophilic brush polymer PPEGMEMA with hydrophobic polyamidoamine (PAMAM) dendron and PCL to form amphiphilic brush-dendritic-linear copolymers. The amphiphilic brush-dendritic-linear copolymers can self-assemble into spherical micellar structures in aqueous solution. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012