Micellization and Mobility of Amphiphilic Poly(2-oxazoline) Based Block Copolymers Characterized by 1H NMR Spectroscopy

Three amphiphilic diblock poly(2-oxazoline) copolymers composed of the hydrophilic poly(2-methyl-2-oxazoline) and hydrophobic poly(2-alkyl-2-oxazoline) with alkyl = pentyl (P1), heptyl (P2), and nonyl side chain (P3) lengths of the hydrophobic block were synthesized by ring-opening cationic polymerization. These polymers form micelles in water above their critical micelle concentration. The temperature-dependent stability of the micellar aggregates was analyzed by DLS and turbidity measurements as well as pyrene solubilization between 20 and 80 °C in water. Moreover, the chemical composition of the block copolymers was determined by 1H NMR spectroscopy. In particular, it was possible to quantify the degree of aggregations of the individual groups of both blocks by including the chemical composition into the derived equations. It could be shown by varying the temperature that both the chemical composition and the degree of micellization depend on the number of bonds of the considered structural groups of t...