Supramolecular Helix–Helix Block Copolymers
Anna Croom
Kylie B. Manning
Marcus Weck
10.1021/acs.macromol.6b01410.s001
https://acs.figshare.com/articles/journal_contribution/Supramolecular_Helix_Helix_Block_Copolymers/3923205
Two chemically distinct
monotelechelic helical polymers were synthesized
using anionic and reversible addition–fragmentation chain-transfer
(RAFT) polymerizations. A chiral poly(isocyanide) block was obtained
using a palladium–ethynyl complex modified with the <i>N</i><sup>1</sup>,<i>N</i><sup>3</sup>-bis(6-butyramidopyridin-2-yl)-5-hydroxyisophthalamide
(Hamilton wedge) moiety as a catalyst employing anionic polymerization.
A complementary barbiturate-functionalized chain-transfer agent was
used to polymerize chiral <i>N</i>-(1-(naphthalen-2-yl)ethyl)methacrylamides
by RAFT polymerization. The assembly into helix–helix supramolecular
block copolymers in chloroform via hydrogen bonding was analyzed by <sup>1</sup>H NMR spectroscopy, resulting in an average measured association
constant of (9.5 ± 0.5) × 10<sup>3</sup> M<sup>–1</sup>. After block copolymer formation, the secondary structures of both
helical polymers were maintained within the block copolymer, as evidenced
by circular dichroism and infrared spectroscopies. Films were prepared
from a 1:1 mixture of polymers in solution and were analyzed by WAXS
and DSC to evaluate organization in the solid state. While diblock
formation in the solution phase is readily obtainable, there was little
evidence supporting a self-assembly assisted microstructure in the
solid state. This work demonstrates a synthetic methodology for obtaining
two telechelic helical polymers capable of supramolecular assembly
in solution toward the goals of developing multifunctional polymeric
ensembles.
2016-09-28 19:07:55
block copolymer formation
barbiturate-functionalized chain-transfer agent
N 1
N 3
Hamilton wedge
1 H NMR spectroscopy
RAFT polymerization
diblock formation
monotelechelic helical polymers
WAXS
supramolecular assembly
DSC
chiral
block copolymer
solution phase
helical polymers
telechelic helical polymers