The PS-b-P4VP diblock copolymers were synthesized by sequential living anionic polymerization in THF using a laboratory autoclave (1 L, Büchi AG). Styrene was polymerized first for 30 min using sec-BuLi as initiator at -80 °C. After complete conversion of styrene, a sample was taken for GPC and MALDI-ToF analyses. Subsequently, 1,1-diphenylethylene was added to the living polystyryllithium (equimolar amount to initiator), followed by the addition of 4-vinylpyridine (4VP). After 4 h the polymerization was terminated with degassed methanol followed by precipitation in deionized water to isolate the diblock copolymer. The average molecular weights of the PS-b-P4VP diblock copolymers were determined from 1 H-NMR (CDCl3), utilizing the absolute molecular weight of the PS precursor obtained by MALDI-ToF MS for signal calibration. As the solubility of the P4VP block in THF strongly decreases with its chain length , micellization and, thus, a significant increase in solution viscosity occurred during the synthesis of the diblock copolymers with high P4VP fractions. Nevertheless, polymerization of 4VP proceeds within the core of the formed micelles to yield the desired diblock copolymers. However, this resulted in an increase in dispersity with increasing P4VP weight fraction (Table ). The diblock copolymer S39V61 162 was additionally purified by extraction with cyclohexane/THF (1/1 v/v) over night to remove a small fraction of PS homopolymer formed by termination upon addition of 4VP.