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Six new bifunctional bis(trithiocarbonate)s were explored as RAFT agents for synthesizing amphiphilic triblock copolymers ABA and BAB, with hydrophilic "A" blocks made from N-isopropylacrylamide and hydrophobic "B" blocks made from styrene. Whereas the extension of poly(N-isopropylacrylamide) by styrene was not effective, polystyrene macroRAFT agents provided the block copolymers efficiently. End group analysis by 1 H NMR spectroscopy supported molar mass analysis and revealed an unexpected side reaction for certain bis(trithiocarbonate)s, namely a fragmentation to simple trithiocarbonates while extruding ethylene-trithiocarbonate. The amphiphilic block copolymers with short polystyrene blocks are directly soluble in water and self-organize into thermo-responsive micellar aggregates.

Amphiphilic poly(2-alkyl-2-oxazoline) diblock copolymers of 2-methyl-2-oxazoline (MOx) building the hydrophilic block and either 2-nonyl-2-oxazoline (NOx) for the hydrophobic or 2-(1H,1H',2H,2H'-perfluorohexyl) -2-oxazoline (FOx) for the fluorophilic block were synthesized by sequential living cationic polymerization. The polymer amphiphiles form core/shell micelles in aqueous solution as evidenced using small-angle neutron scattering (SANS). Whereas the diblock copolymer micelles with a hydrophobic Nox n block are spherical, the micelles with the fluorophilic FOx n are slightly elongated, as observed by SANS and TEM. In water, the micelles with fluorophilic and lipophilic cores do not mix, but coexist.

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.