Papers - SAKAI Go
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Uota Masafumi, Hayashi Yuuichi, Yoshimura Takumi, Kawasaki Hideya, Sakai Go, Kijima Tsuyoshi
Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2007 ( 0 ) 681 - 681 2007
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan
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Kawasaki H., Sakai G., Kijima T.
Applied Surface Science 253 ( 3 ) 1512 - 1516 2006.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Surface Science
The shape transformation of platinum (Pt) nanosheets with a uniform thickness of as thin as 3.5 ± 1 nm supported on graphite was investigated by in situ atomic force microscopy (AFM). The AFM observations revealed the shape transformation and the coalescence in preferred directions for the Pt nanosheets at room temperature (25 °C), which is much lower than the melting point of bulk metallic platinum (1769 °C). The behavior may be attributed to the high surface energy for the edge parts of Pt nanosheets with the small curvature of the nanometer scale. © 2006 Elsevier B.V. All rights reserved.
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Synthesis of resorcinol-based polymer nanowires templated by surfactant assemblies
Fujikawa D., Uota M., Yoshimura T., Sakai G., Kijima T.
Polymer Preprints, Japan 55 ( 1 ) 2006.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan
Recently, we have reported the synthesis of resorcinol-formaldehyde (RF) polymer nanospheres and microwires in the presence of cationic surfactant as a template. Here we report the synthesis and formation mechanism of RF polymer nanowires of 80-300nm diameter by a similar reaction using TMB. The coexisting effect of alcohol on the morphological properties of RF polymers is also reported.
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Kawasaki H., Uota M., Yoshimura T., Fujikawa D., Sakai G., Kijima T.
Journal of Colloid and Interface Science 300 ( 1 ) 149 - 154 2006.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Colloid and Interface Science
One-dimensional (1-D) self-assemblies of Pt nanoparticles on a graphite surface have been synthesized via a template-directed sintering process of individual nanoparticles, using nonionic/cationic mixed hemicylindrical micelle templates of dodecyldimethylamine oxide surfactant at graphite/solution interfaces. The dimension and morphology of Pt nanoparticles can be widely controlled by the concentration of Pt ions equivalent to the mixing ratio of nonionic and cationic species in the surfactant micelle. This approach could be extended to fabricate a wide range of self-assembling metallic nanostructures on surfaces using various nonionic/cationic mixed micelle-like self-assemblies carrying metal ions at interfaces, while providing a fundamental insight into a 1-D self-assembly from individual nanoparticles. © 2006 Elsevier Inc. All rights reserved.
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One-Dimensional Assemblies of Platinum Nanoparticles on a Graphite Surface Using Nonionic/Ionized Mixed Hemicylindrical Micelle Templates Reviewed
Hideya Kawasaki, Masafumi Uota, Takumi Yoshimura, Daisuke Fujikawa, Go Sakai, Tsuyoshi Kijima
Journal of Colloid and Interface Science 300 149 - 154 2006.6
Language：English Publishing type：Research paper (scientific journal)
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Synthesis of micro-mesoporous bimodal silica nanoparticles using lyotropic mixed surfactant liquid-crystal templates Reviewed
Hiroshi Mori, Masafumi Uota, Daisuke Fujikawa, Takumi Yoshimura, Takeshi Kuwahara, Go Sakai, Tsuyoshi Kijima
Microporous and Mesoporous Materials 91 172 - 180 2006.5
Language：English Publishing type：Research paper (scientific journal)
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Mori H., Uota M., Fujikawa D., Yoshimura T., Kuwahara T., Sakai G., Kijima T.
Microporous and Mesoporous Materials 91 ( 1-3 ) 172 - 180 2006.4
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Microporous and Mesoporous Materials
Micro-mesoporous bimodal silica nanoparticles with a particle diameter of as small as 40-90 nm have been synthesized by a two-step reaction based on the polymerization of silicate (TEOS) species confined to the mixed surfactant hexagonal-structured liquid-crystal (LC) templates of nonaethyleneglycol dodecylether (C 12 EO 9 ) and polyoxyethylene (20) sorbitan monostearate (Tween60) or eicosaethyleneglycol octadecyl ether (C 18 EO 20 ). After pre-aging for water-insolubilization, the LC phase was kept in contact with dilute aqueous solution of ammonium acetate to achieve full condensation of silicate species. The catalyst-free pre-aging treatment induces the separation of the LC phase into domains and the subsequent water-phase-in-contact process se rves to maintain the hexagonal framework by removing the ethanol evolved through hydrolysis. On calcination the hexagonal array of mixed surfactant cylindrical micelles in the LC templates is converted into a hexagonal structure of mesopores with some irregularity in pore arrangement, separated by silica walls with irregularly arranged micropores. Throughout aging and calcination, the hexagonal framework of the silicate-loaded LC or condensed particles in the Tween60 based mixed surfactant system contract to yield silica nanoparticles with mesopores of ∼5 nm diameter and ∼2 nm-thick silica walls. In contrast, the framework in the other system remarkably expands to form mesopores of 4.6 nm diameter and silica walls of as thick as 4.7 nm, along with 1.5-2 times larger micropore volume and specific surface area. The striking difference between the structural parameters in both systems is arisen from the opposing effects due to the hydrophilic triple-branched or linear polyoxyethylene (PEO) chains of Tween60 and C 18 EO 20 molecules. © 2005 Elsevier Inc. All rights reserved.
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FUJIKAWA Daisuke, UOTA Masafumi, YOSHIMURA Takumi, SAKAI Go, KIJIMA Tsuyoshi
Chemistry letters 35 ( 4 ) 432 - 433 2006.4
Language：Japanese Publishing type：Research paper (scientific journal)
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Fujikawa D., Uota M., Yoshimura T., Sakai G., Kijima T.
Chemistry Letters 35 ( 4 ) 432 - 433 2006.4
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Chemistry Letters
Thermosetting polymer nanospheres and nanowires have been synthesized by the NaOH-catalyzed polymerization of resorcinol and formaldehyde in the presence of cetyltrimethyl-ammonium bromide as a core template together with/without trimethylbenzene as an additive and topotactically converted into their carbonized forms. Copyright © 2006 The Chemical Society of Japan.
DOI： 10.1246/cl.2006.432
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Surfactant-templated Synthesis of Resorcinol-Formaldehyde Polymer and Carbon Nanostructures: Nanospheres and Nanowires Reviewed
Daisuke Fujikawa, Masafumi Uota, Takumi Yoshimura, Go Sakai, Tsuyoshi Kijima
Chemistry Letters 35 ( 4 ) 432 - 433 2006.4
Language：English Publishing type：Research paper (scientific journal)
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Morphological control of silica using polymer nanostructures
Okazaki Taro, Fujikawa Daisuke, Uota Masafumi, Sakai Go, Kijima Tsuyoshi
Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2006 ( 0 ) 425 - 425 2006
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan
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Study on morphological control of ceramic materials using polymer nanostrucrures
Fujikawa Daisuke, Okazaki Taro, Higuchi Yutaka, Uota Masafumi, Sakai Go, Kijima Tsuyoshi
Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2006 ( 0 ) 348 - 348 2006
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan
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Shinbori Tomohiro, Uota masashi, Sekita masami, Sakai Gou, Kijima Tuyoshi
Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2006 ( 0 ) 192 - 192 2006
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan
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Synthesis and Characterization of Carbon / Sn nanocomposites
Uota Masafumi, Karasima Takeshi, Yoshimura Takumi, Sakai Go, Kijima Tsuyoshi
Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2006 ( 0 ) 127 - 127 2006
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan
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酒井 剛
Electrochemistry 74 ( 10 ) 856 - 856 2006
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Electrochemical Society of Japan
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Fujikawa D., Uota M., Yoshimura T., Sakai G., Kijima T.
Polymer Preprints, Japan 54 ( 2 ) 4775 - 4776 2005.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan
Nanostructural polymer materials have been synthesized by resorcinol-formaldehyde copolymerization in the presence of CTAB with or without TMB. The resulting polymers in the TMB-free systems varied in morphology from spherical particles 250-400nm in diameter to microwires 10-30μm in diameter with an increase of NaOH content, x. in the TMB added systems, nanowires 80-300nm in diameter were obtained in place of the spherical polymers at the same NaOH content. It was also found that the nanostructure polymers are calcined in carbons while keeping their morphologies.
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Synthesis and template effects of resorcinol-based polymer nanostructures
Fujikawa D., Uota M., Yoshimura T., Sakai G., Kijima T.
Polymer Preprints, Japan 54 ( 1 ) 2005.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Polymer Preprints, Japan
Recently, we have reported the synthesis of phenol-furfural (or formaldehyde) polymer nanotubes in the presence of cationic surfactant as the template. But it was unsuccessful to apply these nanotubes to proton conductors and carbon precursors, due to chemical and thermal instability of their frameworks. Here we report the synthesis of nanostructural polymer materials through resorcinol-formaldehyde copolymerization in the presence of CnTAB (n=16, 18).
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Kawasaki H., Uota M., Yoshimura T., Fujikawa D., Sakai G., Annaka M., Kijima T.
Langmuir 21 ( 24 ) 11468 - 11473 2005.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Langmuir
Single-crystalline platinum nanosheets have been prepared via a new methodology based on the chemical reduction of a platinum salt (H 2 PtCl 6 ) with hydrazine at a graphite/solution interface, using polyoxyethylene (20)sorbitan monostearate (Tween 60) based self-assembly (hemicylindrical micelle) templates. The platinum nanosheets with a uniform thickness of as thin as 3.5 ± 1 nm are surface-smooth and continuous over relatively large length scales of micrometer sizes. In striking contrast to the Tween 60 based system, no Pt nanosheets are obtained with nonaethylene glycol monododecyl ether (C 12 EO 9 ) and polyoxyethylene (23) dodecyl ether (C 12 EO 23 ). No Pt nanosheets are also obtainable with a laterally homogeneous layer of Tween 60 formed at the silica/solution interface. These results indicate that surfactant Tween 60 molecules with a triple polyoxyethylene structure, as well as their hemicylindrical micelle templates, play an essential role for the formation of the Pt nanosheets. It is also suggested that the interfacially directed growth of Pt metals within the aqueous shells of the Tween 60 hemicylindrical micelles induces the thin Pt crystals as thick as the aqueous shells. The present approach could be extended to prepare a wide range of novel nanostructures of noble metals, using various micelle-like self-assemblies at interfaces. © 2005 American Chemical Society.
DOI： 10.1021/la051247i
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Single-Crystalline Platinum Nanosheets from Nonionic Surfactant 2-D Self-Assemblies at Solid/Aqueous Solution Interfaces
共著者：H. Kawasaki, M. Uota, T. Yoshimura, D. Fujikawa, G. Sakai, M. Annaka, T. Kijima
Langmuir, Vol. 21, No. 24, 11468-11473 (2005). 21 ( 24 ) 11468 - 11473 2005.11
Language：English Publishing type：Research paper (scientific journal)
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SAKAI Go, NAKATANI Tomoe, YOSHIMURA Takumi, UOTA Masafumi, KIJIMA Tsuyoshi
Chemistry letters 34 ( 10 ) 1364 - 1365 2005.10
Language：Japanese Publishing type：Research paper (scientific journal)