Amphiphilic gradient copolymers containing fluorinated 2-phenyl-2-oxazolines: Microwave-assisted one-pot synthesis and self-assembly in water

Here, we present the one-step synthesis of 2(m-difluorophenyl)-2-oxazoline and its use as a monomer for microwave-assisted statistical cationic ring-opening copolymerizations (CROP). Well-defined amphiphilic gradient copolymers, as evidenced by the polymerization kinetics, were prepared using 2-ethyl-2-oxazoline as comonomer and methyl tosylate as initiator in nitromethane at 140 degrees C. The resulting gradient copolymers (DP = 60 and 100) were characterized by means of size exclusion chromatography and H-1 NMR spectroscopy. In the second part, we focus on a detailed study of the self-assembly of the copolymers in aqueous solution using atomic force microscopy and dynamic light scattering. Both methods revealed the self-assembly of the gradient copolymers into spherical micelles. To quantify the influence of the fluorine atoms and the monomer distribution on the self-assembly, a comparative study with gradient copolymers of 2-phenyl-2-oxazoline and 2-ethyl-2-oxazoline was performed. (c) 2008 Wiley Periodicals, Inc.