Aromatic Polyethers with Low Polydispersities from Chain-Growth Polycondensation

Yokozawa, Tsutomu; Suzuki, Yukimitsu; Hiraoka, Shûichi

doi:10.1021/ja011499f

Cited by 73 publications

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“…We have recently succeeded in synthesizing welldefined condensation polymers such as polyamide, 14,15 polyether, 16 and polyester 17 via a chain-growth polymerization mechanism by virtue of selective activation of the polymer end groups as a result of differences in substituent effects between the monomer and the polymer. 18 An example of chain-growth condensation polymerization for the synthesis of aromatic polyamide is shown in Scheme 1(A).…”

Section: Introductionmentioning

confidence: 99%

Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity

Miyakoshi

Yokoyama

Yokozawa

2007

J. Polym. Sci. A Polym. Chem.

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ABSTRACT:We describe the development of chain-growth condensation polymerization for the synthesis of well-defined p-conjugated polymers via a new polymerization mechanism, catalysttransfer polymerization. We first studied the condensation polymerization of Grignard-type hexylthiophene monomer with a Ni catalyst as a part of our research on chain-growth condensation polymerization, and found that this polymerization also proceeded in a chain-growth polymerization manner. However, the polymerization mechanism involving the Ni catalyst was different from that of previous chain-growth condensation polymerizations based on substituent effects; the Ni catalyst catalyzed the coupling reaction of the monomer with the polymer, followed by the transfer of Ni (0)

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Section: Introductionmentioning

confidence: 99%

Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity

Miyakoshi

Yokoyama

Yokozawa

2007

J. Polym. Sci. A Polym. Chem.

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“…Actually, polyethers with low polydispersities were obtained in this polycondensation (Scheme 16). 50 We had thought at first that the chain-growth polycondensation for polyethers was difficult to be attained, because difference of substituent effects between monomer and polymer is small; the hydroxy group of monomer and the ether linkage of polymer are similar electron-donating groups. The point for this successful chain-growth polycondensation is thought to be the use of phenoxide in monomer instead of phenol.…”

Section: Polymerizationmentioning

confidence: 99%

Chain-Growth Polycondensation: Living Polymerization Nature in Polycondensation and Approach to Condensation Polymer Architecture

Yokozawa

Yokoyama

2004

Polym J

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ABSTRACT:In this review article, polycondensation that proceeds in a chain-growth polymerization manner (''chain-growth polycondensation'') for well-defined condensation polymers are described. Our approach to chaingrowth polycondensation is (1) activation of polymer end group by substituent effects changed between monomer and polymer and (2) phase-transfer polymerization in biphase composed of monomer store phase and polymerization phase. In the approach (1), a variety of condensation polymers such as aromatic polyamides, aromatic polyesters, aromatic polyethers, poly(ether sulfone), and polythiophene with defined molecular weights and low polydispersities were obtained. Their polycondensations had all of the characteristics of living polymerization: a linear correlation between molecular weights and monomer conversion maintaining low polydispersities, and control over molecular weights by the feed ratio of monomer to initiator. Taking advantage of the nature of living polymerization in this polycondensation, we synthesized diblock copolymers of different kinds of aromatic polyamides and of aromatic polyamide and conventional polymers such as poly(ethylene glycol), polystyrene, and poly(tetrahydrofuran), as well as triblock copolymers and star polymers containing aromatic polyamide units. Some copolymers were arranged in a supramolecular self-assembly. In the approach (2), the polycondensation of solid monomer dispersed in organic solvent with a phase transfer catalyst (PTC) was carried out, where solid monomer did not react with each other, and the monomer transferred to organic solvent with PTC reacted with an initiator and the polymer end group selectively in organic solvent, to yield well-defined polyesters.KEY WORDS Chain-Growth Polycondensation / Polycondensation / Living Polymerization / Controlled Polymerization / Architecture / Polyamides / Polyesters / Polyethers / Polythiophenes / Polymerization can be classified into two categories: chain polymerization and step polymerization. Chain polymerization is initiated by the reaction of monomer and initiator, and then monomers react with the propagating group of polymers. If the chain polymerization proceeds in a living polymerization manner, the molecular weight of polymer is controlled by the feed ratio of monomer to initiator and the molecular weight distribution is narrow. In addition, the molecular weight increases in proportion to monomer conversion while retaining low polydispersity over the whole conversion range.On the other hand, step polymerization is initiated by the reaction of monomers with each other, and propagation involves the reactions of all kinds of oligomers with themselves, as well as the reactions of those oligomers with monomers. Therefore, it is difficult to control the molecular weight of polymer, and polymer possesses a broad molecular weight distribution. Plotting the molecular weight values and the polydispersity against monomer conversion, the molecular weight does not increase much in the initial and middle stage and is acce...

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“…This new synthetic method was further improved by Lazano et al [13][14][15][16][17] . Recently, using this living polymerization, Yokozawa et al have reported a new synthetic polymer of aromatic polyether (APE) with a very narrow distribution of degree of polymerization 18) . Thus, we could observe an XRD powder pattern for the solid state of APE (See curve 5 of ).…”

Section: Introductionmentioning

confidence: 99%

“…shows the molecular structure of an APE, which has a molecular weight of M w = 2490, and M w /M n = 1.13, here n = 13 18) . The APE molecule is constructed from ether bonds between benzene rings, the ortho-and meta-positions of which are substituted with propyl and nitrile groups, respectively.…”

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Supuramolecular Structure of Self-assembly Fabricated with Novel Aromatic Polyether on Si-wafers

et al. 2008

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A new synthetic polymer of aromatic polyether (APE), having a narrow distribution of molecular weight, formed a specific self-assembly of Langmuir film (L film) on a water surface, which was subjected to surface pressure relaxation when the L film was compressed over 16.5 mN m -1 at 15 . This self-assembly was capable of transferring on silicon-wafers as LB films. We found that, because the XRD patterns for fabricated LB films depended on the crystal face of the silicon-wafer used and moreover increased in diffraction intensity with the increasing number of built-up layers in the LB film, the present LB films showed a kind of epitaxy-like phenomenon. We propose the molecular mechanism explaining that the formation of an ionic supuramolecular structure of APE occurs only on a silicon wafer surface. (RIGAKU,, and AFM and SEM images for LB film were observed by atomic force microscope (Digital Instruments, Nano Scope IIIa) and scanning electron microscope (Hitachi, S-4100), respectively. XPS measurements were performed on a JEOL JPS-9010 with a magnesium filament operating at 10 kV, 10 mA, using the Ka line. 3When a chloroform solution of APE was spread on a water surface without any additive reagents in water subphase, the APE polymer formed a stable Langmuir film (L film) having a transition point. The p-A curves for the APE L film were measured between 5 and 45 on a water surface with surface compression rate of 5 mm min -1 . By the common technique, LB film of APE was fabricated from the L film with transfer rate of 2 mm min -1 at 15 on various kinds of substrates, for instance, Si-wafers, optical glass, CaF 2 , copper plate, mica, and quartz glass. The Siwafer surface consisted of five kinds of crystal faces; [111] RESULTS3 1 p A The APE L film on the pure water surface gave a stable p-A curve with a transition point. The transition pressure increased with increasing inverse temperature; i.e., the transition is exothermic (-36.0 kJ mol -1 ), in contrast with an endothermic transition for L film of the usual fatty acids 20) . This exothermic character may be attributed to the selfassembly of APE molecules on the water surface. After the L film was compressed up to 30 mN m -1 with 5 mm min -1 , the surface pressure of the compressed L film relaxed with time even the surface area remained constant at 15 .shows the results of the surface relaxation at various pressures of initial compression. Equilibrium pressure was established at 16.5 mN m -1 after about 2 hr at 15 . However, when the film was compressed to the pressure less than the transition pressure, the phenomenon of surface relaxation was not clearly recognized. These phenomena suggest that the APE L film would be converted spontaneously into some different kinds of physical states with the progress of surface relaxation. 2In order to investigate the physical state of APE film after surface relaxation, the L films before and after transition were respectively transferred to one layer on the [111] face of Si-wafer. LB film was fabricated on the ...

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Aromatic Polyethers with Low Polydispersities from Chain-Growth Polycondensation

Cited by 73 publications

References 10 publications

Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity

Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity

Chain-Growth Polycondensation: Living Polymerization Nature in Polycondensation and Approach to Condensation Polymer Architecture

Supuramolecular Structure of Self-assembly Fabricated with Novel Aromatic Polyether on Si-wafers

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