Article,
Supramolecular Block Copolymers by Seeded Living Polymerization of Perylene Bisimides
J. Am. Chem. Soc., 141 (30): 12044--12054 (July 2019)
DOI: 10.1021/jacs.9b04935
Abstract
Living covalent polymerization has been a subject of intense research
for many decades and has culminated in the synthesis of a large variety of block
copolymers (BCPs) with structural and functional diversity. In contrast, the research
on supramolecular BCPs is still in its infancy and their generation by living processes
remains a challenge. Here we report the formation of supramolecular block
copolymers by two-component seeded living polymerization of properly designed
perylene bisimides (PBIs) under precise kinetic control. Our detailed studies on
thermodynamically and kinetically controlled supramolecular polymerization of three
investigated PBIs, which contain hydrogen-bonding amide side groups in imide
position and chlorine, methoxy, or methylthio substituents in 1,7 bay-positions,
revealed that these PBIs form kinetically metastable H-aggregates, which can be
transformed into the thermodynamically favored J-aggregates by seed-induced living
polymerization. We show here that copolymerization of kinetically trapped states of
one PBI with seeds of another PBI leads to the formation of supramolecular block
copolymers by chain-growth process from the seed termini as confirmed by UV/vis spectroscopy and atomic force microscopy
(AFM). This work demonstrates for the first time the formation of triblock supramolecular polymer architectures with A-B-A
and B-A-B block pattern by alternate two-component seeded polymerization in a living manner.
