Synthetic approaches for the preparation of cyclic polymers

Laurent, Boyd A.; Grayson, Scott M.

doi:10.1039/b809916m

Cited by 458 publications

(468 citation statements)

References 44 publications

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“…[1][2][3][4][5] In particular, the emergence of various cyclic topologies based on linear polymers has recently drawn great attention from academia because of the unique traits of these systems, such as increased glass transition temperature, lower viscosity and smaller hydrodynamic radius due to the lack of a chain end group effect. [1][2][3][4][5][6][7][8][9][10] In addition, cyclic block copolymers have received interest due to selfassembly characteristics that deviate from the typical behaviours of their linear analogues. 3,5,[11][12][13][14][15][16][17][18][19][20][21][22][23][24] In the case of micelle formation in solution, cyclic block copolymers were reported to form relatively more compact micelles than their linear analogues.…”

Section: Introductionmentioning

confidence: 99%

Well-defined and stable nanomicelles self-assembled from brush cyclic and tadpole copolymer amphiphiles: a versatile smart carrier platform

et al. 2017

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This study reports the first well-defined and stable nanomicelles (20 − 30 nm in diameter) self-assembled from amphiphilic brush (comb-like) cyclic and tadpole-shaped copolymers composed of hydrophobic n-decyl and hydrophilic 2-(2-methoxyethoxy)ethoxy) ethyl bristle blocks based on a poly(glycidyl ether) backbone. The micelle formation behaviour and structural details were investigated by synchrotron X-ray scattering analysis in a rigorous and complementary manner. The amphiphilic brush cyclic topology facilitates more compact and stable aggregation behaviour in the micelle core and a more densely packed corona, which prevents intermicellar aggregation. The presence of a hydrophobic component with brush cyclic topology inside the core is identified as the primary micelle stabilizing factor, enabling stable core aggregation and sharper core-corona interface formation. The presence of a hydrophilic brush cyclic component in the corona is determined as the secondary micelle stabilizing factor, helping nullify the corona penetration by polymer chains from other micelles and ultimately prevent the intermicellar aggregation-mediated collapse of the micellar structure. Overall, the brush cyclic topology was confirmed to be beneficial for forming highly stable nanomicelles with an extremely narrow (pseudo-monodisperse) size distribution compared with conventional linear topology and tadpole topologies. All the results of this study provide a unique opportunity for designing advanced functional high-performance amphiphilic materials for nanomicelles that are unattainable by other conventional methods and broadening their applications in various fields, including drug delivery, biomedical imaging, foods, cosmetics, smart coatings, photonics and molecular electronics.

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Section: Introductionmentioning

confidence: 99%

Well-defined and stable nanomicelles self-assembled from brush cyclic and tadpole copolymer amphiphiles: a versatile smart carrier platform

et al. 2017

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“…[56][57][58] Although cyclic polymers have attracted much interest in both polymer synthesis and physics, the synthesis of cyclic polymers has long suffered from the difficulties of tedious preparation and troublesome purification. 12,59,60 Generally, the synthesis of cyclic polymers is accomplished using two major methods: the cyclization of linear-shaped precursors with a homo or hetero bifunctional group Topology-transformable polymers T Takata and D Aoki at both ends and ring expansion polymerization through the continuous addition of monomers to the cyclic initiator. Although the cyclization of linear-shaped precursors is the most commonly used method, it requires high reactivity at both polymer ends and efficient cyclization under high dilution conditions to prevent intermolecular reactions.…”

Section: Application Of M2rmentioning

confidence: 99%

Topology-transformable polymers: linear–branched polymer structural transformation via the mechanical linking of polymer chains

Takata

Aoki

2017

Polym J

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In this review article, we discuss the synthesis and dynamic nature of macromolecular systems that have mechanically linked polymer chains capable of undergoing a topology transformation driven by a rotaxane molecular switch. The rotaxane linking of polymer chains plays a crucial role in these systems. A linear polymer possessing a crown ether/sec-ammonium salt-type [1] rotaxane moiety at the axle chain terminal was prepared via the rotaxane linking of a single polymer chain. A linear-cyclic polymer topology transformation was achieved via the movement of the wheel component from one end to the other end of the axle component using the rotaxane macromolecular switch function. The successful synthesis of a macromolecular [2]rotaxane (M2R) possessing a single polymer axle and one crown ether wheel led to a variety of unique applications, such as the development of topology-transformable polymers and the synthesis of rotaxane crosslinked polymers (RCPs). The introduction of a polymer chain to the wheel component of M2R (rotaxane linking of two polymer chains) produced a rotaxane-linked AB block copolymer that transformed its topology from linear to branched. Furthermore, a rotaxane-linked three-component polymer and an ABC triblock copolymer were synthesized and transformed to the corresponding 3-arm star (co)polymers, and the transformation was confirmed by measuring the hydrodynamic volume change. The structural transformation of 4-arm and 6-arm star polymers was also accomplished using the dynamic mobility of a similar rotaxane. As a useful application, M2R-based vinylic crosslinkers (RCs) were prepared and applied to the synthesis of RCPs, whereby the addition of RCs into radical polymerization systems of vinyl monomers afforded polymers with excellent toughness by enhancing both of tradeoff properties that cannot be achieved using typical covalent crosslinkers.

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“…[1][2][3][4][5][6][7] To date, cyclic polymers with different structures such as diblock, [8] triblock terpolymer, [9] eight-shaped, [10] and tadpole copolymers [11][12][13][14][15] have been synthesized either by end-to-end linking or ring-expansion process. [16][17][18][19][20] Among them, tadpole homo/copolymers consisting of a ring polymer as a head and one linear polymer as a tail, are very interesting for rheology and self-assembly studies, since they combine two topologies in the same molecule.…”

Section: Introductionmentioning

confidence: 99%

Polyethylene‐Based Tadpole Copolymers

Alkayal

Zhang

Bilalis

et al. 2017

Macro Chemistry & Physics

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Novel well-defined polyethylene-based tadpole copolymers {(c-PE)-b-PS, PE: polyethylene, PS: polystyrene} with ring PE head and linear PS tail are synthesized by combining polyhomologation, atom transfer radical polymerization (ATRP), and Glaser coupling reaction. The OH groups of the 3-miktoarm star copolymers (PE-OH) 2 -b-PS, synthesized by polyhomologation and ATRP, are transformed to alkyne groups by esterification with propiolic acid, followed by Glaser cyclization and removal of the unreacted linear with Merrifield's resin-azide. The characterization results of intermediates and final products by high-temperature size exclusion chromatography, 1 H NMR spectroscopy, and differential scanning calorimetry confirm the tadpole topology.

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Synthetic approaches for the preparation of cyclic polymers

Cited by 458 publications

References 44 publications

Well-defined and stable nanomicelles self-assembled from brush cyclic and tadpole copolymer amphiphiles: a versatile smart carrier platform

Well-defined and stable nanomicelles self-assembled from brush cyclic and tadpole copolymer amphiphiles: a versatile smart carrier platform

Topology-transformable polymers: linear–branched polymer structural transformation via the mechanical linking of polymer chains

Polyethylene‐Based Tadpole Copolymers

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