Effect of polymer architecture of amphiphilic poly(2-oxazoline) copolymers on the aggregation and aggregate structure

The micelle formation of five poly(2-oxazoline) diblock, triblock and gradient copolymers in water was investigated using fluorescence correlation spectroscopy. The polymers were synthesized by consecutive or simultaneous living cationic polymerization of 2-methyl-2-oxazoline for the hydrophilic and 2-nonyl-2-oxazoline for the hydrophobic polymer segments. Fractions of the polymers were fluorescence-labeled at the polymer termini with TRITC for the FCS measurements. The hydrodynamic radii of solubilized polymer unimers and of the aggregates (micelles) were determined in a concentration range of 10(-8)-10(-3) m and were found to depend in a characteristic way on the polymer architecture.