Dendronized Poly(2-oxazoline) Displays within only Five Monomer Repeat Units Liquid Quasicrystal, A15 and σ Frank–Kasper Phases
Liquid quasicrystals (LQC) have been discovered in self-assembling benzyl ether, biphenylmethyl ether, phenylpropyl ether, biphenylpropyl ether and some of their hybrid dendrons and subsequently in block copolymers, surfactants and other assemblies. These quasiperiodic arrays, which lack long-range...
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Published in | Journal of the American Chemical Society Vol. 140; no. 49; pp. 16941 - 16947 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
WASHINGTON
American Chemical Society
12.12.2018
Amer Chemical Soc |
Subjects | |
Online Access | Get full text |
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Summary: | Liquid quasicrystals (LQC) have been discovered in self-assembling benzyl ether, biphenylmethyl ether, phenylpropyl ether, biphenylpropyl ether and some of their hybrid dendrons and subsequently in block copolymers, surfactants and other assemblies. These quasiperiodic arrays, which lack long-range translational periodicity, are approximated by two Frank–Kasper periodic arrays, Pm3̅n cubic (Frank–Kasper A15) and P42/mnm tetragonal (Frank–Kasper σ), which have been discovered in complex soft matter in the same order and compounds. Poly(2-oxazoline)s dendronized with (3,4)nG1 minidendrons (where n denotes an alkyl chain, C n H2n+1) self-organize into the Pm3̅n cubic phase (n = 14 and 15) and, as reported recently, the P42/mnm tetragonal phase (n = 16). However, no LQC of a poly(2-oxazoline) is yet known. Here we report the synthesis, structural and retrostructural analysis of a dendronized poly(2-oxazoline) with n = 17 which self-organizes not only into the LQC but also in the above two Frank–Kasper approximants. All three phases are observed from the same polymer within a very narrow range of degree of polymerization that corresponds to only five monomer repeat units (5 ≤ DP ≤ 10). The formation of the Pm3̅n cubic, P42/mnm tetragonal and LQC phases from a single polymer chain within such a narrow range of DP raises the questions of how and why each of these phases is self-organized. This system may provide a model for theoretical investigations into the self-organization of soft matter into Frank–Kasper and related periodic and quasiperiodic arrays. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0002-7863 1520-5126 |
DOI: | 10.1021/jacs.8b11103 |