Synthesis of nanocylinders consisting of graft block copolymers by the photo‐induced ATRP technique

Ishizu, Koji; Kakinuma, Hirokazu

doi:10.1002/pola.20491

Cited by 57 publications

(53 citation statements)

References 29 publications

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“…The HBPs underwent photo-and thermal-living radical polymerization that originated from the cleavage and recombination of the thiocarbonyl groups on the HBP surface. [17][18][19][20][21][22][23] The living radical polymerization produced not only the additional chain polymerization of the monomers to the surface of the HBP, such as in graft polymerization, but also induced the addition of polymeric segments to the other polymeric segments at the surface of the HBP. Therefore, the HBPs in the disclination lines could be further polymerized using UV irradiation to immobilize these disclination lines before the mobilization or merging of these disclination lines and the formation of micrometer-sized HBP particles.…”

Section: Methodsmentioning

confidence: 99%

“…[17][18][19][20][21][22][23] Therefore, the physical properties of the HBPs, such as solubility to a host phase, molecular weight, viscosity, refractive index and fluorescence, can be easily controlled. If the spatial distribution and arrangement of HPBs are further controlled, the range of applications of these materials will expand extensively, especially in photonics and electronics.…”

Section: Introductionmentioning

confidence: 99%

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Spatial distribution control of polymer nanoparticles by liquid crystal disclinations

Higashiguchi

Yasui

Ozawa

et al. 2012

Polym J

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A perylene-labeled hyper-branched polymer with a mesogenic shell was observed to migrate toward a field with a large distortion of directors. This polymer was captured by disclination lines of 1/2 strength in its nematic and chiral nematic phases using a confocal fluorescence microscope. In particular, the well-aligned particle array of the hyper-branched polymers was produced by the chiral nematic phase confined in a wedge cell. The hyper-branched polymer with its mesogenic shell was completely dissolved into an isotropic phase. Immediately after a phase transition to the chiral nematic phase, numerous droplets appeared over a wide area owing to phase separation, and the free droplets moved toward the disclination lines via Brownian motion. Finally, the droplets were rapidly attracted to the disclination lines and trapped within them. Polymer Journal (2012) 44, 632-638; doi:10.1038/pj.2012.44; published online 11 April 2012Keywords: confocal fluorescence polarizing microscope; disclination line; fluorescence; hyper-branched polymer; liquid crystal INTRODUCTION Controlling the spatial arrangements of molecules or particles on different length scales is one of the crucial issues of bottom-up nanotechnology. 1,2 Recently, dispersions of colloidal particles and polymers in nematic or cholesteric phases have attracted considerable attention because they demonstrate a diversity of self-assembled arrangements, such as linear or circle chains and 2D lattices. [3][4][5][6] The long-range force of self-assembly originates from the elastic energy of the distortions produced around the particles in the nematic phase. [7][8][9][10][11][12][13][14] The particles have also been observed to be attracted to and to migrate toward a disclination or domain boundary in the nematic field. Because the director distortions of nematic liquid crystals 15,16 are large near the disclination, the elastic energy is higher near the disclination than in uniform director regions. 3 The particles near the disclination might be exposed to an attractive force toward the disclination core, where the highest director gradient is formed.In terms of particle polymers, hyper-branched polymers (HBPs), a novel class of polymer with highly branched structures and large numbers of end groups, are attractive because dendritic chain structures can be produced via an one-pot reaction, and the chemical structure and molecular weight of HBPs can be easily modified. [17][18][19][20][21][22][23] Therefore, the physical properties of the HBPs, such as solubility to a host phase, molecular weight, viscosity, refractive index and fluorescence, can be easily controlled. If the spatial distribution and arrangement of HPBs are further controlled, the range of applications of these materials will expand extensively, especially in photonics and electronics.In this paper, we synthesize perylene-labeled HBPs with mesogenic shells (1) that can be dispersed in a nematic liquid crystal and study

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spatial distribution control of polymer nanoparticles by liquid crystal disclinations

Higashiguchi

Yasui

Ozawa

et al. 2012

Polym J

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“…Matyjaszewski's 32 and Müller's groups 33 have also synthesized double-cylinder-type brushes by the ''grafting from'' approach using ATRP. More recently, Ishizu and Kakinuma 34 have established the preparation method of double-cylinder-type brushes by the similar ''grafting from'' photo-induced ATRP of PSD with vinyl monomers [first monomer, t-butyl methacrylate (BMA); second monomer, styrene or MMA] (see Scheme 4). A copper complex, CuCl/bipyridine (bpy) activated reversibly the domant polymer chains via a DC transfer reaction such as CuCl(DC)/bpy, and it was dynamic equilibrium which was responsible for the controlled behavior of the polymerizations of BMA and MMA.…”

Section: G'mentioning

confidence: 99%

Architecture of Multi-Component Copolymer Brushes: Synthesis, Solution Properties and Application for Nanodevices

Ishizu

2004

Polym J

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ABSTRACT:In this review article, we describe the architecture of multi-component copolymer brushes. These copolymer brushes can be classified into tree types, i.e., double-cylinder-type, prototype, and block-type. Double-cylinder-type copolymer brushes were prepared by free-radical polymerization of corresponding diblock macromonomer or by the ''grafting from'' approach using atom transfer radical polymerization (ATRP). Alternating free-radical copolymerization of the mixture of two macromonomers provided prototype copolymer brushes. ATRP was applied to the synthesis of AB-type brush-block-brush (block-type) copolymers. All copolymer brushes were molecularly dissolved in a dilute solution due to densely branched side chains and took geometrically anisotropic conformation such as cylinder with increasing aspect ratio. In self-assembly process of amphiphilic prototype copolymer brushes in water, hierarchical generations from small rods to large rods were observed, because copolymer brushes exhibited phase-separated hydrophobic/hydrophilic domains. Moreover, binding of anionic/nonionic polyeletrolyte prototype brushes with cationic linear polyelectrolyte formed an interesting complex of a high order by electrostatic interaction. On the other hand, the molecular wires in electronic nanodevices were prepared by forming conducting polypyrroles with an internal core of double-cylider-type copolymer brushes as templates, where as the outer cylinder parts play the role of an insulator. [DOI 10.1295/polymj.36.775] KEY WORDS Multi-component Copolymer Brush / Double-cylinder-type / Prototype / Blocktype / Macromonomer / ATRP / Aternating Copolymerization / Molecular Wire / Binding / Nanostructured polymers are of rapidly growing interest because of their sized-coupled properties. Generally, the branched polymer has a smaller hydrodynamic dimension than a linear polymer with the same molecular weight. The interest in branched polymers arises from their compactness and their enhanced segment density. Recently, a new class of branched architectural polymers, such as nanocylinders, is attracting attention with expectation that their unique structures may result in unusual properties. It is well known that comb polymers with densely grafted side chains in a good solvent can adopt a worm-like cylinder brush conformations, in which the side chains are stretched in the direction normal to the backbone, owing to the excluded-volume interaction. The polymerization of macromonomers provides regular multi-branched polymers with dense branching. Since both the degree of polymerization (DP n ) and the length of branches are varied, poly(macromonomer)s, often so-called ''polymer brushes'', are interesting models for the study of branched polymers.1-9 More recently, we have systematically investigated the architecture of multi-component copolymer brushes. Figure 1 shows the illustration of three types of multi-component copolymer brushes. Various strategies can be designed to construct such structures. For example, one strategies for the...

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“…We have also established a preparation method of double-cylinder-type copolymer brushes by grafting from photoinduced ATRP of multifunctional polystyrene (PSDC) having N,N-diethyldithiocarbamate (DC) pendant groups with vinyl monomers [first monomer, t-butyl methacrylate; second monomer, styrene or methyl methacrylate (MMA)]. 21 On the basis of the earlier experimental results, we speculate that the rigid nanocylinders will be able to construct by crosslinking of internal cylindrical domains of functionalized double-cylinder-type copolymer brushes.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of functionalized double‐cylinder‐type copolymer brushes and crosslinking of internal cylindrical domains

Ishizu

Takano

Ochi

2007

J of Applied Polymer Sci

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Photoinduced atom transfer radical polymerization (ATRP) was applied to the synthesis of doublecylinder-type copolymer brushes. The procedure included the following steps: (1) photoinduced ATRP of multifunctional polystyrene (PSDC) having N,N-diethyldithiocarbamate (DC) pendant groups with t-butyl acrylate (BA) and (2) subsequent photoinduced ATRP of methyl methacrylate (MMA) with this PBA brush polyinitiator provided double-cylinder-type brushes [PSDC-graft-(PBA-block-PMMA)]. Solution properties of such doublecylinder-type brushes were investigated by dynamic light scattering. As a result, these copolymer brushes exhibited an isotropic conformation in solution. After hydrolysis of PBA blocks, we obtained amphiphilic copolymer brushes: PSDC-graft-[poly(acrylic acid) (PAA)-block-PMMA]. Crosslinking of PAA internal cylindrical domains was performed by the reaction of PAA blocks with ethylenediamine.

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Synthesis of nanocylinders consisting of graft block copolymers by the photo‐induced ATRP technique

Cited by 57 publications

References 29 publications

Spatial distribution control of polymer nanoparticles by liquid crystal disclinations

Spatial distribution control of polymer nanoparticles by liquid crystal disclinations

Architecture of Multi-Component Copolymer Brushes: Synthesis, Solution Properties and Application for Nanodevices

Synthesis of functionalized double‐cylinder‐type copolymer brushes and crosslinking of internal cylindrical domains

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