Synthesis and characterization of PEGylated comb-like cationic polymer by polycondensation and ATRP

PEGylated poly(2-(dimethylamino)ethyl methacrylate) with comb-like architecture was synthesized by two-step polymerization. First, poly(oligo(ethylene glycol) malicate) (POEGMA) bearing pendant hydroxyl groups was prepared by direct polycondensation of oligo(ethylene glycol) and malic acid in the presence of scandium triflate as chemoselective catalyst. Then the poly(2-(dimethylamino)ethyl methacrylate) side chains were grafted from the POEGMA backbone by atom transfer radical polymerization (ATRP) after the hydroxyl groups were modified into bromo-ester form, resulting in a PEGylated cationic copolymer with branched architecture.