Topological polymer chemistry by electrostatic self‐assembly

Abstract

Recent developments in topological polymer chemistry are outlined. First, nonlinear polymer topologies are systematically classified on the basis of topological considerations of constitutional isomerism in a series of alkanes (C n H 2nϩ2 ), monocycloalkanes (C n H 2n ), and polycycloalkanes (C n H 2nϪ2 , C n H 2nϪ4 , etc.). Various pairs of topological isomers are identified in randomly coiled, flexible polymer molecules with cyclic and branched structures. An electrostatic self-assembly and covalent fixation strategy has subsequently been developed for the efficient synthesis of a variety of topologically unique polymers, including monocyclic and polycyclic polymers, topological isomers, and topological block copolymers. In this process, new telechelics with moderately strained cyclic onium salt groups carrying multifunctional carboxylate counteranions have been designed as key polymeric precursors. Further extensions of topological polymer chemistry have been achieved by the use of cyclic telechelics (kyklo-telechelics) and cyclic macromonomers, obtainable also by means of the electrostatic self-assembly and covalent fixation process.

Electrostatic self-assembly of thermally responsive zwitterionic poly(N-isopropylacrylamide) and poly(ethylene oxide) modified with ionic groups

“…The approaches to the creation of novel structures are distinguished by the modes of binding the components, either through covalent fixation, or by means of hydrophobic, hydrogen bonding, or electrostatic self-assembly. Instead of performing complicated chemical modifications, attractive intermolecular interactions have been triggered by changes in temperature, pH, ionic strength, or by addition of surfactants and functional polymers to yield systems stable under certain conditions [1][2][3]. The continuing interest in such environmentally responsive structures, also known as smart systems, stems from their potential application as drug delivery systems, chemical separators, sensors, and catalysts.…”

Synthesis of Polymeric Topological Isomers through Electrostatic Self‐Assembly and Covalent Fixation with Star Telechelic Precursors

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Besides a simple ring construction, [15] there exist three dicyclic polymer topologies, [16] that is, eight-shaped, [17] y-shaped, [18,19] and manacle-shaped [18,20] constructions. Attempts to realize such unusual polymer topologies are an ongoing challenge in synthetic polymer chemistry.…”

“…Attempts to realize such unusual polymer topologies are an ongoing challenge in synthetic polymer chemistry. [13,14] We have recently reported an ''electrostatic self-assembly and covalent fixation'' process by making use of specifically designed linear telechelic polymer precursors having moderately strained cyclic ammonium salt end groups carrying appropriately nucleophilic counteranions like carboxylates. [13,14,[18][19][20][21] A variety of single cyclic and multicyclic, that is, such double-cyclics as eight-shaped, y-shaped, and a triple-cyclic trefoil-shaped, polymer constructions have been effectively produced by this methodology.…”

“…[13,14] We have recently reported an ''electrostatic self-assembly and covalent fixation'' process by making use of specifically designed linear telechelic polymer precursors having moderately strained cyclic ammonium salt end groups carrying appropriately nucleophilic counteranions like carboxylates. [13,14,[18][19][20][21] A variety of single cyclic and multicyclic, that is, such double-cyclics as eight-shaped, y-shaped, and a triple-cyclic trefoil-shaped, polymer constructions have been effectively produced by this methodology. In particular, two of the three dicyclic topologies, namely a pair of constitutional isomers of y-shaped and manacle-shaped polymers, are formed from an assembly comprised of linear bifunctional precursors (1L) and trifunctional carboxylates (2t), in which cations and anions balance the charges (see structures below and Scheme 1a).…”

A novel strategy towards cyclic aliphatic (co)polyesters

“…A novel strategy towards cyclic aliphatic (co)polyesters [23,24]. Although the linear precursors prepared by living/controlled polymerization are well-defined, the unavoidable competition between intramolecular cyclization and intermolecular extension is the major problem to be solved.…”