Ohta, YoshihiroYoshihiroOhtaHuang, Chih FengChih FengHuangLee, Yi HuanYi HuanLeeCHI-AN DAIYokozawa, TsutomuTsutomuYokozawa2023-05-262023-05-262023-01-0110221352https://scholars.lib.ntu.edu.tw/handle/123456789/631422Well-defined block copolymers consisting of hyperbranched polyamide (HBPA) and polystyrene (PSt) are synthesized, and their self-assembled structures in solutions are investigated. Atom transfer radical polymerization (ATRP) of styrene initiated from an HBPA macroinitiator, prepared by the chain-growth condensation polymerization of an AB2 monomer, followed by introduction of an ATRP initiator unit at the focal point, gives the desired block copolymers, PSt-b-HBPAs, with well-defined molecular weight and narrow molecular weight distribution. The block copolymer (PSt/HBPA = 84/16) undergoes self-assembly in toluene to form spherical micelles (≈10–20 nm), but upon addition of methanol to the toluene solution (toluene/methanol = 0.97/0.03), the morphology changes to vesicles. Further addition of methanol (toluene/methanol = 0.90/0.10) leads to an increase in vesicle size (200–300 nm) and the morphology further transforms from vesicles to large aggregates (>100 nm) at toluene/methanol = 0.80/0.20. In the case of PSt-b-HBPA with shorter PSt segments (PSt/HBPA = 76/24 and 60/40), spherical micelles are formed in toluene, but the micelle morphology remains unchanged when 10 wt% methanol is added, though large aggregates (>100 nm) are still formed in toluene/methanol = 0.80/0.20. Interestingly, the morphological transformations of linear/hyperbranched block copolymers are different from those of their double linear block copolymer counterparts.chain-growth condensation polymerization | hyperbranched polymers | linear-hyperbranched block copolymers | micelles | self-assembly | vesiclesjournal article10.1002/macp.2022002982-s2.0-85140216101WOS:000870810500001https://api.elsevier.com/content/abstract/scopus_id/85140216101