研究者詳細 - 中西　和樹

Basic study of the gelation of dimethacrylate-type crosslinking agents 査読有り

Aoki H, Hosoya K, Norisuye T, Tanaka N, Tokuda D, Ishizuka N, Nakanishi K

JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 44 巻 ( 2 ) 頁： 949 - 958 2006年1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：Journal of Polymer Science, Part A: Polymer Chemistry

An investigation was made of the gelation of dimethacrylate-type crosslinking agents in view of an application for separation media. The study mainly centered on a crosslinking agent, glycerol dimethacrylate (GDMA), which is relatively hydrophilic because of a hydroxyl group in the middle of its structure. The gelation of GDMA was compared with that of other hydrophobic crosslinking agents such as ethylene glycol dimethacrylate and 1,6-hexanediol dimethacrylate. The diluents used in the study were toluene, toluene with methanol, and cyclohexanol. The gelation was observed in real time with a charge coupled device camera and dynamic light scattering (DLS). Also, the separated dry gels were extensively characterized with scanning electron microscopy, BET (N2 absorption and desorption isotherm), and Fourier transform infrared. DLS analysis showed a stronger molecular interaction of GDMA gelation in toluene, whereas this interaction was much weaker in an alcoholic solvent such as toluene with methanol or cyclohexanol. This indicated that GDMA gelation might proceed through hydrogen bonding as well as a crosslinking reaction of vinyl groups. © 2005 Wiley Periodicals, Inc.

DOI： 10.1002/pola.21205

Control of light scattering in organic-inorganic hybrid macroporous monoliths

Size exclusion chromatography of standard polystyrenes with a wide range of molecular weight up to 7.45 x 10(6) on monolithic silica capillary columns 査読有り

Ute Koichi, Yoshida Saori, Kitayama Tatsuki, Bamba Takeshi, Harada Kazuo, Fukusaki Eiichiro, Kobayashi Akio, Ishizuka Norio, Minakuchi Hiroyoshi, Nakanishi Kazuki

POLYMER JOURNAL 38 巻 ( 11 ) 頁： 1194 - 1197 2006年

Porous methylsiloxane gel thick film for millimeter-wave antenna substrate prepared by gap filling method 査読有り

Tanaka Takeharu, Kawakami Nobuyuki, Hirano Takayuki, Fukumoto Yoshito, Suzuki Tetsuo, Kanamori Kazuyoshi, Nakanishi Kazuki

MATERIAL AND DEVICES FOR SMART SYSTEMS II 888 巻頁： 251 - + 2006年

Hirao T., Murai S., Fujita K., Nakanishi K., Hirao K.

Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 52 巻 ( 10 ) 頁： 781 - 785 2005年10月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy

The tuning of light scattering strength has been demonstrated for organic-inorganic hybrid monoliths with well-defined through-pores in micrometer range. Macroporous gels having interconnected pores and skeletons are obtained in a system containing methyltrimethoxysilane, water, nitric acid, and methanol using an alkoxy-derived sol-gel method combined with the phase separation. The sizes of pores and skeletons can be controlled by varying molar ratios of water and methanol in the starting compositions which mostly affect the onset of polymerization-induced phase separation in the system. The mercury porosimetry shows that the resultant gels have a sharp pore size distribution, and the average pore diameter increases with increasing the amount of water and methanol. The coherent backscattering measured for the gels formed in between two slide glasses reveals that the transport mean free path of light decreases with decreasing the sizes of pores and skeletons. Pore size dependence of the scattering strength can be qualitatively explained by a Mie scattering calculation using a model in which spherical pores are randomly distributed in methylsiloxane matrix. The results indicate that the scattering strength can be tuned by controlling the sizes of the pores.

DOI： 10.2497/jjspm.52.781

An application of silica-based monolithic membrane emulsification technique for easy and efficient preparation of uniformly sized polymer particles 査読有り

Hosoya K, Bendo M, Tanaka N, Watabe Y, Ikegami T, Minakuchi H, Nakanishi K

MACROMOLECULAR MATERIALS AND ENGINEERING 290 巻 ( 8 ) 頁： 753 - 758 2005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：Macromolecular Materials and Engineering

Uniformly sized polymer particles were prepared by an emulsification and polymerization technique utilizing a silica monolithic membrane, namely the "silica monolithic membrane emulsification technique". In this paper, we utilized silica monolithic membrane as a device for the preparation of uniformly sized polymer particles. A mixture of monomers, diluents and oil-soluble initiator was emulsified into a continuous medium through the silica monolithic membrane and polymerized. The particles obtained had a higher size uniformity than that of particles prepared by previously reported membrane emulsification techniques, such as the Shirasu Porous Glass (SPG) emulsification technique. Through the silica monolithic membrane emulsification technique, we could prepare particles having availability as a possible packing material for solid-phase extraction (SPE) and high performance liquid chromatography (HPLC). © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI： 10.1002/mame.200500006

Experimental validation of the tetrahedral skeleton model pressure drop correlation for silica monoliths and the influence of column heterogeneity 査読有り

Vervoort N, Saito H, Nakanishi K, Desmet G

ANALYTICAL CHEMISTRY 77 巻 ( 13 ) 頁： 3986 - 3992 2005年7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：Analytical Chemistry

This paper describes the use of computational fluid dynamics for the calculation of the flow resistance through computer-generated models resembling silica monoliths. This study was undertaken to determine the effect of skeleton heterogeneity on the flow resistance and, more precisely, to test the hypothesis that increased skeleton heterogeneity decreases the flow resistance. To evaluate the proposed model, 24 real silica monoliths have been prepared using the same method, covering a wide range of skeleton sizes (2.2 μm < d s < 8 μm) and porosities (0.47 < ε < 0.66). The permeability of these monoliths was determined by pressure drop measurements, and structural information was obtained by image analysis of laser scanning confocal microscopy-generated 3D images of the skeleton structure. The results indicate that the presence of preferential flow paths due to an increased heterogeneity of the flow through pore space reduces the flow resistance of monolithic media. It is also shown that the pore size is hence a much better suited scaling dimension than the skeleton size to reduce the permeability of monolithic columns. © 2005 American Chemical Society.

DOI： 10.1021/ac0502798

Silica monolithic membrane as separation medium - Summable property of different membranes for high-performance liquid chromatographic separation 査読有り

Hosoya K, Ogata T, Watabe Y, Kubo T, Ikegami T, Tanaka N, Minakuchi H, Nakanishi K

JOURNAL OF CHROMATOGRAPHY A 1073 巻 ( 1-2 ) 頁： 123 - 126 2005年5月

Monolithic periodic mesoporous silica with well-defined macropores 査読有り

Amatani T, Nakanishi K, Hirao K, Kodaira T

CHEMISTRY OF MATERIALS 17 巻 ( 8 ) 頁： 2114 - 2119 2005年4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：Chemistry of Materials

Monolithic pure silica gels with hierarchical macro-mesoporous structure have been synthesized via a spontaneous sol-gel process from silicon alkoxide using a structure-directing agent and a micelle-swelling agent. A monolithic body with well-defined co-continuous macropores is a result of concurrent phase separation and sol-gel transition induced by the polymerization reaction, whereas the mesopores are templated by the cooperative self-assembly of inorganic species, a structure-directing agent, and a micelle-swelling agent. These bimodal pore systems are formed spontaneously in a closed condition at a constant temperature. The following removal of surfactants by heat-treatment gives silica gels with hierarchical and fully accessible pores in discrete size ranges of micrometers and nanometers. The highly ordered 2D-hexagonal arrays of mesopores have been confirmed by X-ray diffraction measurements and FE-SEM observations. Furthermore, by further additions of the micelle-swelling agent, the mesostructural transition from well-ordered 2D-hexagonal arrays to mesostructured cellular foams (MCF) has been induced accompanied by minor modifications of the micrometer-range structure. © 2005 American Chemical Society.

DOI： 10.1021/cm048091c

High-performance frontal analysis of the binding of thyroxine enantiomers to human serum albumin 査読有り

Kimura T, Nakanishi K, Nakagawa T, Shibukawa A, Matsuzaki K

PHARMACEUTICAL RESEARCH 22 巻 ( 4 ) 頁： 667 - 675 2005年4月

Recent advances in the design of monolithic silica columns: From small to big dimensions. 査読有り

Cabrera K, Kraus A, Minakuchi H, Nakanishi K

ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 229 巻頁： U144 - U144 2005年3月

Insight on structural change in sol-gel-derived silica gel with aging under basic conditions for mesopore control 査読有り

Takahashi R, Nakanishi K, Soga N

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 33 巻 ( 2 ) 頁： 159 - 167 2005年2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：Journal of Sol-Gel Science and Technology

Structural rearrangement of sol-gel-derived silica gel by aging under basic conditions was investigated using small angle X-ray scattering (SAXS) and 29Si nuclear magnetic resonance (NMR). A wet silica gel prepared under acidic conditions had a fractal nature and many unreacted silanols remained on the surface. During aging of the gel in ammonia solution additional Si-O-Si bonds rapidly formed whereas the change in mesoscale structure gradually proceeded. This result was compared with that of simulation modeling the Ostwald ripening i.e. dissolution from positive curvature and reprecipitation on negative curvature. In the simulation structural change in a cluster from fractal nature to particle aggregates was well visualized in 2-dimmensional square lattice. Both scattering profiles calculated from the model clusters and the change in average coordination number of monomers in the cluster well agreed with the experimental SAXS and NMR results respectively. This agreement strongly ensures us that structural change by aging under basic conditions proceeds through the Ostwald ripening. The mesopore size as well as mesopore volume in calcined silica gel is determined by the shrinkage degree during drying and calcination. The sample aged in basic solution restrains the shrinkage because of the growth of particulate structure and retains large size and volume of pores. © 2005 Springer Science + Business Media, Inc.

DOI： 10.1007/s10971-005-5610-9

Titania-coated monolithic silica as separation medium for high performance liquid chromatography of phosphorus-containing compounds 査読有り

Miyazaki S, Miah MY, Morisato K, Shintani Y, Kuroha T, Nakanishi K

JOURNAL OF SEPARATION SCIENCE 28 巻 ( 1 ) 頁： 39 - 44 2005年1月

Formation of photonic structures inSM(2+)-doped aluminosilicate glasses through phase separation 査読有り

Fujita K, Murai S, Nakanishi K, Hirao K

Micromachining Technology for Micro-Optics and Nano-Optics III 5720 巻頁： 261 - 268 2005年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Progress in Biomedical Optics and Imaging - Proceedings of SPIE

Sm2+-doped Al2O3-SiO2 glasses with three-dimensionally interconnected macroporous morphology have been prepared via the alkoxy-derived sol-gel process containing poly (ethylene oxide) and SmCl3·6H2O. The macroporous morphology is obtained by concurrently inducing the phase separation and sol-gel transition. Using a visible laser with the wavelength of 488 nm, the valence state of Sm2+ has been manipulated spatially. When the photoionization of Sm2+ is combined with multiple light scattering in the porous glasses, holes are burned in wave-vector domain. The hole profile can be controlled by adjusting the macroporous morphology.

DOI： 10.1117/12.590712

Topical application of ionic polymers affects skin permeability barrier homeostasis 査読有り

Denda M, Nakanishi K, Kumazawa N

SKIN PHARMACOLOGY AND PHYSIOLOGY 18 巻 ( 1 ) 頁： 36 - 41 2005年

Fabrication of macroporous TiO2 monoliths for photonic applications 査読有り

Konishi J, Fujita K, Nakanishi K, Hirao K

Micromachining Technology for Micro-Optics and Nano-Optics III 5720 巻頁： 233 - 240 2005年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Progress in Biomedical Optics and Imaging - Proceedings of SPIE

Macroporous titania (TiO2) monoliths have been prepared by the sol-gel method including phase separation, and the light-scattering properties have been investigated by means of coherent backscattering. Macroporous TiO 2 gels are obtained in the systems containing aqueous titania colloid and poly(ethylene oxide) (PEO). Three-dimensionally interconnected macroporous structure is formed when the transient structure of phase separation is fixed as the permanent morphology by the sol-gel transition. The domain size of macroporous TiO2 gels can be controlled reproducibly by adjusting the concentration of PEO. During the heat treatment above 1000°C, the TiO 2 skeleton is sintered into fully dense body and the crystalline structure is transformed from anatase to rutile, while maintaining macroporous morphology. We show that the rutile-type TiO2 -based macroporous monoliths are strongly scattering media for visible light.

DOI： 10.1117/12.591059