Development of a new azido-oxazoline monomer for the preparation of amphiphilic graft copolymers by combination of cationic ring-opening polymerization and click chemistry

A new monomer (2-(5-azidopentyl)-2-oxazoline) bearing an azido group was synthesized. The cationic ring-opening copolymerization of this monomer with 2-methyl-2-oxazoline resulted in a well-defined linear polymer backbone with pendant azido groups. Alkynyl-poly(d,l-lactide) was grafted onto the azido groups of poly(oxazoline) via a Huisgen 1,3-dipolar cycloaddition reaction to give a novel amphiphilic graft copolymer [poly(2-methyl-2-oxazoline-co-2-pentyl-2-oxazoline)-g-poly(d,l-lactide)] (P[(MeOx-co-PentOx)-g-LA]). Different graft copolymers were prepared with PLA of different lengths. Preliminary results of the self-association of this copolymer in water indicated the formation of nanoparticles, which suggests this copolymer may have applications as vehicles for drug delivery.