Papers - SAKAI Go
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Effect of Electron Irradiation on Nanogroove-Networked Single-crystalline and Dendritic Polycrystalline Platinum Nanosheets Prepared from Lyotropic Surfactant Liquid-Crystal Templates Reviewed
T. Yoshimura, M. Uota, T. Kuwahara, D. Fujikawa, H. Kawasaki, G. Sakai, T. Kijima
Materials Research Bulletin 43 1282 - 1290 2008.3
Language：English Publishing type：Research paper (scientific journal)
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Additive-stabilized hexagonally ordered mixed lyotropic liquid crystal Reviewed
D. Li, D. Fujikawa, T. Yoshimura, M. Uota, G. Sakai, T. Kijima
Journal of Molecualr Liquids 138 113 - 119 2008.3
Language：English Publishing type：Research paper (scientific journal)
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Kijima T., Shinbori T., Sekita M., Uota M., Sakai G.
Journal of Luminescence 128 ( 3 ) 311 - 316 2008.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Luminescence
A new nanostructure-mediated approach was demonstrated to synthesize Eu 3+ -doped yttrium oxysulfates Y 2 O 2 SO 4 :Eu 3+ giving rise to abnormally enhanced Eu 3+ emission. Yttrium and europium salts, sodium dodecylsulfate (SDS), and urea at various Eu 3+ concentrations were reacted in aqueous solution at 80, 85, and 87 °C to yield Eu 3+ -doped dodecylsulfate-templated yttrium oxide mesophases with straight-layered (S-type), concentric-layered (C-type) and layer-to-hexagonal transient-layered (T-type) structures, respectively. On calcination at 1000 °C, all of these mesophases were converted into Y 2 O 2 SO 4 :Eu 3+ to exhibit luminescence bands including the 5 D 0 - 7 F 2 transition with a tendency in intensity to saturate or reach a maximum at 10-12 mol% Eu doping. The Eu 3+ emissions for Y 2 O 2 SO 4 :Eu 3+ mediated by the T- and C-type mesophases were enhanced in intensity by a factor of about two and three times, respectively, stronger than those for not only compositionally the same sulfate Y 2 O 2 SO 4 :Eu 3+ obtained from yttrium-based sulfates but also Y 2 O 3 :Eu 3+ obtained in the SDS-free system. In contrast, the emission intensities for the S-type-mesophase-mediated Y 2 O 2 SO 4 :Eu 3+ were close to those for the latter sulfates. The abnormally enhanced emission is likely based on specific deformation of sulfate groups induced through the conversion of concentric dodecylsulfate-layers to straight sulfate-layers in the oxysulfate framework upon calcination. © 2007 Elsevier B.V. All rights reserved.
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Additive-stabilized hexagonally ordered mixed lyotropic liquid crystal
Li D., Fujikawa D., Yoshimura T., Uota M., Go sakai, Kijima T.
Journal of Molecular Liquids 138 ( 1-3 ) 113 - 119 2008.2
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Molecular Liquids
A strategy for preparing mixed lyotropic liquid crystals (LLCs) possessing a stable 2-D hexagonal mesostructure is demonstrated, which can be controlled easily and reproducibly through the use of both hydrophobic dopings and inorganic cations serving as additives. By using small molecules such as LiCl and anthracene, respectively, the cylindrical micelles of mixed amphiphiles can spontaneously assemble into 2-D hexagonal mesophase. This kind of mixed amphiphiles may be used as stable templates for synthesis of templated nanomaterials. © 2007 Elsevier B.V. All rights reserved.
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Size controlled spherical carbones templated by surfactant assemblies
Ohtsuka Akio, Kai Nanami, 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 2008 ( 0 ) 596 - 596 2008
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan
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Hydrothermal transformation of high-surface-area b-Ni(OH)<sub>2</sub> into nanostructures
Sakai Go, Miyazaki Makoto, Kijima Tsuyoshi
Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2008 ( 0 ) 694 - 694 2008
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan
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Kawasaki H., Uota M., Yoshimura T., Fujikawa D., Sakai G., Arakawa R., Kijima T.
Langmuir 23 ( 23 ) 11540 - 11545 2007.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Langmuir
We report the fabrication of self-organized surfactant nanofibers containing platinum ions on a highly oriented pyrolytic graphite (HOPG) surface from mixed solutions of hexadecyltrimethylammonium hydroxide (C16TA0H) and hydrogen hexachloroplatinate (IV) (H2PtCl6). The fibrous surfactant self-assembly was stable in air, even after being soaked in water, in contrast to surfactant hemicylindrical micelles, which are stable only at graphite/solution interfaces. The results show that the graphite surface served as an essential template for the specific formation of fibrous surfactant self-assemblies. In addition, when surfactant nanofibers containing metal ions were treated with hydrazine, platinum nanoparticles concentrated in the nanofibers formed on the HOPG surface. We also prepared surfactant nanofibers containing gold ions on HOPG surfaces and formed gold nanoparticles in the nanofibers. © 2007 American Chemical Society.
DOI： 10.1021/la701020s
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Performance evaluation of MEA by accumulating structure of catalyst layer
Shibata Koichiro, Yaoka Toshinari, Tashima Daisuke, Sakai Go, Otsubo Masahisa
Memoirs of the Faculty of Engineering, Miyazaki University 36 127 - 131 2007.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Miyazaki University
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Kondo Y., Harima Y., Hyakutake K., Yamada N., Uota M., Sakai G., Kijima T.
Colloid and Polymer Science 285 ( 9 ) 1019 - 1027 2007.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Colloid and Polymer Science
The composite films of poly(lactic acid) (PLA) doped with glucosamine(Gluc)-formaldehyde(FA) polymer/sodium dodecylbenzenesulfonate (SDBS) complexes at 1-5 wt% were synthesized to demonstrate striking improvement of their structural and mechanical properties. The polymer complexes were obtained by the hydrothermal polymerization of Gluc and FA at a molar ratio of 1:2 in the presence of SDBS. The atomic ratios of S in -SO 3 - to N in -NH 3 - (=S/N) in the polymer complexes limitedly range from 0.52 to 0.69, indicating that the complexation develops through the nonstoichiometric reaction between -NH 3 + groups of (Gluc-FA) polymer and -SO 3 - ones of SDBS and 31-48% of the -NH 3 + groups remain unbound. The PLA composite film doped with 1 wt% (Gluc-FA)/SDBS showed the elongation-at-break of as large as 194% compared with 37% for PLA film, together with an appreciable increase of the crystallites size (D 200 ) of PLA from 21.8 to 33.3 nm. © Springer-Verlag 2007.
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Fujikawa D., Uota M., Sakai G., Kijima T.
Carbon 45 ( 6 ) 1289 - 1295 2007.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Carbon
The NaOH-catalyzed polymerization of resorcinol (R) and formaldehyde (F) confined to the vesicular assemblies of cetyltrimethylammonium bromide as a core template mixed with 1,3,5-trimethylbenzene and tert-butanol (tBuOH) as cosurfactants yielded RF polymer/cetyltrimethylammonium composite nanowires and nanospheres depending on the amount of tBuOH. Carbonization of the resulting nanpolymers led to microporous carbon nanowires of 45-240 nm diameter and nanospheres of 260-650 nm diameter. Similar but a little modified reactions successfully resulted in monodispersed carbon nanospheres of ca. 280 nm diameter as well as monodispersed carbon nanowires of ca. 70 nm diameter with a high surface area of 1777 m 2 /g. The present approach could be further extended to the synthesis of a wide range of carbon nanomaterials by using various surfactants and cosurfactants. © 2007 Elsevier Ltd. All rights reserved.
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Self-organization of Surfactant-Metal Ion Complex Nanofibers on Graphite Surfaces and Their Application to the Fibrously Concentrated Platinum Nanoparticles Formation Reviewed
H. Kawasaki, M. Uota, T. Yoshimura, D. Fujikawa, G. Sakai, R. Arakawa, T. Kijima
Langmuir 23 11540 - 11545 2007.4
Language：English Publishing type：Research paper (scientific journal)
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Kijima T., Nishida Y., Fujikawa D., Uota M., Yoshimura T., Sakai G.
Journal of Molecular Liquids 133 ( 1-3 ) 54 - 60 2007.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Molecular Liquids
The structural change and phase transition in the mixed surfactant liquid crystalline (LC) system of nonaethyleneglycol dodecylether (C 12 EO 9 ), polyoxyethylene (20) sorbitan monostearate (Tween 60) and water has been studied on addition of primary alcohols C n H 2n+1 OH (C n OH, n = 10, 12, and 14) or replacement of C 12 EO 9 with C n OH. In the alcohol-added systems, the C 12 EO 9 /Tween 60/C n OH/H 2 O mixture at a 1:1:x:60 molar ratio for n = 12 undergoes hexagonal to layered phase transition just beyond the critical composition of x = 0.5, whereas the phase transitions for n = 10 and 14 occur at lower compositions. In the alcohol-replaced C 12 EO 9 /Tween 60/C n OH/H 2 O systems at a 1 - y:1:y:60 molar ratio, the hexagonal LC structures for n = 10 and 12 are kept up to y = 0.5 and 0.7, respectively, although the hexagonal phase for n = 14 is transformed into a layered structure beyond y = 0.3. The y = 0.3 composition for n = 12 affords a very highly ordered hexagonal LC, even compared with the alcohol-free phase. The rod-to-rod distance for the hexagonal LCs consisting of cylindrical rodlike micelles in the alcohol-replaced systems increases remarkably with an increase of y, in contrast to a slight increase for the same parameter in the alcohol-added systems. The phase transition mechanism is also discussed. © 2006 Elsevier B.V. All rights reserved.
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Synthesis and characterization of poly(lactic acid) and glucosamine-formaldehyde/dodecylbenzenesulfonate composite films
Y. Kondo, Y. Harima, K. Hyakutake, N. Yamada, M. Uota, G. Sakai, T. Kijima
Colloid and Polymer Science 285 1019 - 1027 2007.3
Language：English Publishing type：Research paper (scientific journal)
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Shape-controlled Nanocarbons from Vesicular Assemblies-templated Resorcinol-Formaldehyde Nanopolymers Reviewed
Daisuke Fujikawa, Masafumi Uota, Go Sakai, Tsuyoshi Kijima
Carbon 45 1289 - 1295 2007.3
Language：English Publishing type：Research paper (scientific journal)
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Long-Chain Alcohol Induced Phase Transition in Lyotropic Mixed Polyoxyethylene-type Surfactant Liquid-Crystals Reviewed
Tsuyoshi Kijima, Yuki Nishida, Daisuke Fujikawa, Masafumi Uota, Takumi Yoshimura, Go Sakai
Journal of Molecular Liquids 133 54 - 60 2007.2
Language：English Publishing type：Research paper (scientific journal)
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Sakai G., Yoshimura T., Isohata S., Uota M., Kawasaki H., Kuwahara T., Fujikawa D., Kijima T.
Advanced Materials 19 ( 2 ) 237 - 241 2007.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Advanced Materials
The synthesis of nanogroove-network-structured single-crystalline Platinum (Pt) nanosheets and the method for loading the nanogrooved Pt nanosheets on a Carbon support using a mixed-surfactant templating approach is discussed. The resulting nanogrooves-networked Pt on the carbon support (Pt/C) was also demonstrated to exhibit fairly high electrocatalytic activity for oxygen reduction reactions. The nanogroove-network structured single-crystalline Pt nanosheets were obtained by the reduction of Na 2 PtCl 6 confined to the lyotropic mixed LCs of polyoxyethylene and nanoethyleneglycol dodecylether. Atomic force microscopy (AFM) images of the resulting black powders showed a multilayered aggregate of rounded to elliptic nanosheets. The results showed that the Pt material consisted of single-crystalline nanosheets that are composed of pseudo-2D irregular shape networks of loosely interconnected Pt nanoleaves.
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Synthesis of Nanogroove-Network Structured Platinum Nanosheets and Their Carbon-supported Forms by Mixed Surfactant-Templating Approach Reviewed
Go Sakai, Takumi Yoshimura, Shusaku Isohata, Masafumi Uota, Hideya Kawasaki, Takeshi Kuwahara, Daisuke Fujikawa, Tsuyoshi Kijima
Advanced Materials 19 237 - 241 2007.1
Language：English Publishing type：Research paper (scientific journal)
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Evaluation of Characteristics of MEA as Multi Catalyst Layer (3).
Yaoka Toshinari, Hidaka Hiroaki, Tashima Daisuke, Sakai Go, Otsubo Masahisa
Record of Joint Conference of Electrical and Electronics Engineers in Kyushu 2007 ( 0 ) 452 - 452 2007
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Committee of Joint Conference of Electrical, Electronics and Information Engineers in Kyushu
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Nagatomo Yu, 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 2007 ( 0 ) 682 - 682 2007
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan
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Synthesis and characterization of high surface area nickel hydroxide by rapid hydrolysis method
Sakai Go, Miyazaki Makoto, 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 ) 139 - 139 2007
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan