研究者詳細 - 大久保　貴広

機能構築微粒子調製法によるTiB2のナノ微細化査読

その他リンク： http://orcid.org/0000-0001-5907-3683

大久保貴広, 西山勝廣, 小野哲央, 丹羽進, 河野通, 酒井秀樹, 小石真純, 阿部正彦

粉体および粉末冶金 52 ( 1 ) 3 - 9 2005年

Preparation and Characterization of Nonionic Surfactant Vesicles Using Supercritical Carbon Dioxide 査読

K. Ri, S. Yamaguchi, P. Wongtrakul, S. Hashimoto, K. Otake, T. Ohkubo, H. Sakai, M. Abe

材料技術 23 340 - 347 2005年

Effects of Dialkyldimethylammonium Bromides on the Membrane Properties of Cationic Liposomes 査読

Akiko Inagaki, Koji Tsuchiya, Hideki Sakai, Tomohiro Imura, Takahiro Ohkubo, Nobuyuki Tsubaki, Shoko Yokoyama, Masahiko Abe

Journal of Oleo Science 54 ( 7 ) 383 - 388 2005年

記述言語：英語掲載種別：研究論文（学術雑誌）

Cationic liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and dialkyldimethylammonium bromides (DLAB, DMAB, DPAB or DSAB) were prepared by the Bangham method, and the effect of the alkyl chain length of dialkyldimethylammonium bromide on the membrane properties of the liposomes was examined in terms of the trapping efficiency liposomal shape and phase transition temperature. Furthermore, the effect of stearylamine (SA) on the liposomal membrane properties was also investigated. Large unilamellar vesicles (LUVs) with a diameter of approximately 1.0 ~ 1.5 μm were formed by mixing small amounts of cationic substances, not only dialkyldimethylammonium bromides, but also SA. The trapping efficiency of the mixed liposomes was greater than that of the DPPC liposomes since the DPPC liposomes were multilamellar vesicles. The maximum trapping efficiency of the mixed liposomes was obtained at 0.05 mole fractions of the cationic substances. Furthermore, dialkyldimethylammmonium bromides with longer alkyl chains, DSAB, DPAB and DMAB, formed cationic substance-rich liposomes with DPPC, and they had the second maximum trapping efficiency at 0.75 ~ 0.9 mole fractions of cationic substance. © 2005, Japan Oil Chemists' Society. All rights reserved.

DOI： 10.5650/jos.54.383

EXAFS Study of Electrolytic Nanosolution Confined in Interstitial Nanospaces of SingleWall Carbon Nanohorn Colloids 査読

その他リンク： http://orcid.org/0000-0001-5907-3683

T. Ohkubo, Y. Hattori, H. Kanoh, T. Konishi, H. Sakai, M. Abe, D. Kasuya, M. Yudasaka, S. Iijima, T. Fujikawa, K. Kaneko

Physica Scripta 685 - 685 2005年

Cluster-associated filling of water in hydrophobic carbon micropores 査読

T Kimura, H Kanoh, T Kanda, T Ohkubo, Y Hattori, Y Higaonna, R Denoyel, K Kaneko

JOURNAL OF PHYSICAL CHEMISTRY B 108 ( 37 ) 14043 - 14048 2004年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

The pore-wall chemistry of activated carbon fiber (ACF) was controlled by heating in Ar and H-2. The ACF structures were characterized from various levels, and interaction of water vapor with the micropores of ACF was directly measured by calorimetry. Two kinds of pitch-based ACFs with different pore widths (w) (P5, w = 0.7 nm, and P20, w = 1.0 nm) were used. P20 was treated at 1273 K in a gas flow of Ar or H-2 for 1 h to modify its surface properties. Adsorption isotherms of water on the two ACFs at 303 K showed different features, which are possibly caused by the pore width difference. The surface modification by the heat treatment of P20 changed its pore structure, leading to different water adsorption behavior. The mechanisms of water adsorption and desorption can be discussed through the differential or integral heat of water adsorption or desorption. Water adsorbs on the functional groups located at the surface of P20 with an adsorption heat comparable to the heat of condensation at relatively low P/P-0, causing the cluster formation of water molecules. The removal of such functional groups by heat treatment decreases the adsorption heat at low pressure. The differential heat abruptly increases at filling in all cases, indicating a structural formation of water from a clustered form to a highly ordered form.

DOI： 10.1021/jp048934n

Control of particle alignment in water by an alternating electric field 査読

その他リンク： http://orcid.org/0000-0001-5907-3683

M Abe, A Yamamoto, M Orita, T Ohkubo, H Sakai, N Momozawa

LANGMUIR 20 ( 17 ) 7021 - 7026 2004年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

We attempted to align a large number of silica particles dispersed in aqueous solution by controlling the alternating electric field between the two electrodes (400 mum apart). Relatively large particles (9.9 mum) were found to align forming strings in the direction parallel to the electric field while relatively small particles (2.0 and 4.9 mum) were observed to align making stripes in the direction perpendicular to the field. The number of stripes formed by particles between the electrodes increased with increasing frequency of the alternating field. This peculiar perpendicular particle alignment appeared when the contribution to particle alignment of electroosmotic flow exceeded that of dielectric polarization and the osmotic flow was found to be stronger around the particles than in the vicinity of the electrode surface.

DOI： 10.1021/la0490801

Three-dimensional arrangements of polystyrene latex particles with a hyperbolic quadruple electrode system 査読

M Abe, M Orita, H Yamazaki, S Tsukamoto, Y Teshima, T Sakai, T Ohkubo, N Momozawa, H Sakai

LANGMUIR 20 ( 12 ) 5046 - 5051 2004年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

An attempt was made to arrange polystyrene latex particles (2, 5, and 10,mum in diameter) dispersed in aqueous media making use of their dielectrophoresis and electrophoresis with a hyperbolic quadruple electrode system. Application of a high-frequency ac field enabled the particles to arrange themselves between the electrodes forming a particle monolayer due to the negative dielectrophoretic force. Simultaneous application of high-frequency ac and dc fields caused the particles to gather in the region surrounded by the electrodes to form particle multilayers. Appropriate choice of the way of applying an electric field thus allowed the reversible control of particle arrangements (monolayer, multilayer, dispersion). Reapplication of an ac field to the particle layers produced highly dense particle multilayers.

DOI： 10.1021/la036465v

Solution Properties of Sulfate-Type Fluoro-Hybrid Anionic Surfactants with a Benzene Ring in Their Molecules 査読

Chengxu Sun, Haruhiko Miyazawa, Yukishige Kondo, Norio Yoshino, Koki Abe, Masanobu Sagisaka, Boonyarach Kitiyanan, Takahiro Ohkubo, Hideki Sakai, Masahiko Abe

Journal of Oleo Science 53 ( 8 ) 371 - 376 2004年

記述言語：英語掲載種別：研究論文（学術雑誌）

Two novel sulfate-type fluoro-hybrid anionic surfactants with a bezene ring in their molecules, F8H3OS and F6H5OS, were synthesized and their solution properties were investigated. Both of the hybrid surfactants were found to show an outstanding surface and interfacial tension lowering ability. F8H3OS formed compact micelles with small aggregation numbers and the micelles coagulated with increase in the surfactant concentration, while F6H5OS formed micelles at its low concentration and the micelles were transformed into vesicles at high concentrations of the surfactant. © 2004, Japan Oil Chemists' Society. All rights reserved.

DOI： 10.5650/jos.53.371

Synthesis and Photochemical Properties of Cationic Surfactant Having a Spiropyran Group 査読

その他リンク： http://orcid.org/0000-0001-5907-3683

Control of viscoelasticity using redox reaction 査読

Tsuchiya, K, Orihara, Y, Kondo, Y, Yoshino, N, Ohkubo, T, Sakai, H, Abe, M

Journal of the American Chemical Society 126 ( 39 ) 12282 - 12283 2004年

C. Sun, K. Arimitsu, K. Abe, T. Ohkubo, T. Yamashita, H. Sakai, M. Abe

材料技術 22 ( 6 ) 229 - 237 2004年

Electrically Controlled Two-Dimensional Cluster Formation of Polystyrene Particles and Cluster Fixation with Adsorbed Polyelectrolyte 査読

Hiroyuki Yamazaki, Masanori Orita, Toshio Sakai, Takahiro Ohkubo, Hideki Sakai, Takashi Yamashita, Tohru Kohno, Masahiko Abe

Journal of Oleo Science 53 ( 9 ) 437 - 444 2004年

記述言語：英語掲載種別：研究論文（学術雑誌）

An attempt was made to orderly arrange a large number of polystyrene particles dispersed in aqueous medium on the electrode surface and fix the formed particle arrangement. The measuring cell used consisted of two transparent indium tin electrodes 500 μm apart from each other in the vertical direction. The gap between the electrodes was filled with a dispersion of polystyrene particles (5 μm size) and the behavior of the particles in electric fields applied between the electrodes was on-site observed with an optical microscope. Simultaneous application of DC and AC fields caused polystyrene particles to form single-layered clusters each consisting of several tens particles on the lower electrode. Densely arranged clusters were formed for the particles with polyallylamine hydrochloride (PAH), a cationic polyelectrolyte, adsorbed on their surface upon application of DC and AC fields and the clusters formed remained unbroken after removal of the fields. No cluster formation was observed, however, for the particles after adsorbing the cationic polyelectrolyte and then poly (sodium styrenesulfonate) (PSS), an anionic polyelectrolyte. These findings suggested that particle arrangement and its fixation of polystyrene particles are appreciably affected by polyelectrolyte adsorption. © 2004, Japan Oil Chemists' Society. All rights reserved.

DOI： 10.5650/jos.53.437

Ordered Arrangement of Polystyrene Latex Particles Conducted by Electrophoresis and Dielectrophoresis 査読

その他リンク： http://orcid.org/0000-0001-5907-3683

Hideki Sakai, Masanori Orita, Hiroyuki Yamazaki, Toshio Sakai, Nobuyuki Momozawa, Takahiro Ohkubo, Masahiko Abe

Journal of Oleo Science 53 ( 7 ) 355 - 362 2004年

記述言語：英語掲載種別：研究論文（学術雑誌）

Polystyrene latex particles in 5 μm diameter were arranged one-, two- and three-dimensionally by electrophoresis and dielectrophoresis using the following electrodes, plate-plate electrode, plate-needle electrode and hyperbolic quadruple electrode. Application of an AC field brought about a one dimensional latex particle arrangement, resulting a pearl chain, by dielectrophoretic force on using the plate-plate electrode. Particle arrangement could be tuned by changing AC bias frequecy when using the plate-needle electrode. With the hyperbolic quadruple electrode, particles could be closely packed in a two-dimensional arrangement with application of the AC field. Simultaneous application of high frequency AC and DC fields resulted in arrangement in the region surrounded by the electrodes with consequent particle multilayer formation. Reversible control of particle arrangement (dispersion, monolayer, and multilayer) can thus be carried out through appropriate choice of electrode and mode of electric field application. © 2004, Japan Oil Chemists' Society. All rights reserved.

DOI： 10.5650/jos.53.355

Structural anomalies of Rb and Br ionic nanosolutions in hydrophobic slit-shaped solid space as revealed by the EXAFS technique 査読

その他リンク： http://orcid.org/0000-0001-5907-3683

T Ohkubo, Y Hattori, H Kanoh, T Konishi, T Fujikawa, K Kaneko

JOURNAL OF PHYSICAL CHEMISTRY B 107 ( 49 ) 13616 - 13622 2003年12月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

The hydration structure of RbBr electrolytic solutions confined in slit-shaped nanospaces of carbon was determined with the extended X-ray absorption fine structure (EXAFS) technique and related analysis. The nitrogen adsorption isotherms at 77 K were measured to evaluate the porosity of RbBr-deposited carbon samples. The EXAFS results indicate that the electrolytic solution confined in hydrophobic nanospaces has a restricted hydration structure depending on the average pore width of the nanospaces. Also the asymmetric-field effect of slit-pore geometry on the formation of unique hydration structures of ions in nanospaces was unveiled with the analysis of EXAFS spectra. A marked decrease of the hydration number around a Rb ion was observed in slit-shaped nanospaces, indicating the compressed hydration structure around a Rb ion restricted in slit-shaped nanospaces. The distorted hydration structure around a Br ion in the slit-shaped pore of 0.7 nm was formed to increase the hydration number, though partially dehydrated structure can be formed in a 1.1 nm pore. The cluster-mediated ordered structure of water molecules can play an important role in forming a dehydrated structure around a Br ion confined in the 1.1-nm pore.

DOI： 10.1021/jp0343685

Growth of Highly-Oriented Silica Nanotubes of Mica Substrate 査読

Hideki Sakai, Ryoko Takubo, Takahiro Ohkubo, Aritomo Yamaguchi, Toshiaki Kakihara, Masahiko Abe

Journal of the Japan Society of Colour Material 76 ( 12 ) 476 - 479 2003年

Nanosolution as a new turn of nanoconfinement for fluids 査読

T Ohkubo, H Kanoh, K Kaneko

AUSTRALIAN JOURNAL OF CHEMISTRY 56 ( 10 ) 1013 - 1016 2003年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：C S I R O PUBLISHING

Towards the goal of nanoscale molecular systems, littlework has been undertaken on ionic solutions at the nanoscale ('nanosolution', NSN). Functional nanoporous materials can be applied to confine, and thereby allow study of molecular assemblies and NSNs; electrically neutral hydrophobic pores reveal a particularly marked confinement effect. This article summarizes the properties and structures of molecules confined within nanospaces and the pioneering work on the distorted and partially dehydrated structures of NSNs.

DOI： 10.1071/CH03109

Pore structures of ZSM-5 synthesized in the mesopore spaces of a carbon aerogel 査読

その他リンク： http://orcid.org/0000-0001-5907-3683

YS Tao, H Tanaka, T Ohkubo, H Kanoh, K Kaneko

ADSORPTION SCIENCE & TECHNOLOGY 21 ( 2 ) 199 - 203 2003年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：MULTI SCIENCE PUBL CO LTD

A mesoporous ZSM-5 monolith several millimetres in size has been synthesized employing the template method and using a carbon aerogel with uniform mesopores. Measurement of the pore-size distribution using nitrogen adsorption showed a bimodal pore system of mesopores and micropores whose average pore widths were 8 nm and 0.51 nm, and whose volumes were 0.09 cm(3)/g and 0.34 cm(3)/g, respectively.

DOI： 10.1260/026361703769013925

Structure of ultra-thin RbBr "solution" in carbon nanospace 査読

T Ohkubo, H Kanoh, Y Hattori, T Konishi, K Kaneko

NANOTECHNOLOGY IN MESOSTRUCTURED MATERIALS 146 61 - 64 2003年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

The hydration structure of RbBr electrolytic solution confined in carbon nanospaces was determined with EXAFS technique and related analyses. The analytical results indicate that the electrolytes confined in hydrophobic nanospaces have an incomplete dehydration structure, because of an intensive restriction and cluster formation of adsorbed water molecules in the nanospaces.

DOI： 10.1016/S0167-2991(03)80327-0

Restricted hydration structures of Rb and Br ions confined in slit-shaped carbon nanospace 査読

その他リンク： http://orcid.org/0000-0001-5907-3683

T Ohkubo, T Konishi, Y Hattori, H Kanoh, T Fujikawa, K Kaneko

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 124 ( 40 ) 11860 - 11861 2002年10月

Hydrogen-bond change-associated gas adsorption in inorganic-organic hybrid microporous crystals 査読

S Onishi, T Ohmori, T Ohkubo, H Noguchi, L Di, Y Hanzawa, H Kanoh, K Kaneko

APPLIED SURFACE SCIENCE 196 ( 1-4 ) 81 - 88 2002年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

CO2 is almost vertically adsorbed and desorbed at 0.0106-0.0073 relative pressure at 273 K, respectively, on the preevacuated Cu-complex. crystals which have no open micropores from the crystallographic structures. These vertical adsorption and desorption steps are named gate effects. Here, guest water molecules are evolved during the pre-evacuation at 373 K and the crystal structure with X-ray diffraction examination does not change due to pre-evacuation. The X-ray diffraction patterns also show no change before and after the steps. The adsorption/desorption gate effects and the remarkable hysteresis are explained in terms of the molecular valve model stemming from the reorientation of the bending vibration of the hydrogen bonding. This model can explain the observed hysteresis in the gate effect; the spring constant difference of the molecular valve for desorption and adsorption is estimated to be a similar order to that of the hydrogen bond in bulk ice. (C) 2002 Elsevier Science B.V All rights reserved.

DOI： 10.1016/S0169-4332(02)00048-X