研究者詳細 - 中原　佳夫

論文 - 中原　佳夫

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Ultra-thin films of polysilsesquioxanes possessing 3-methacryloxypropyl groups as gate insulator for organic field-effect transistors

Yoshio Nakahara, Haruna Kawa, Jun Yoshiki, Maki Kumei, Hiroyuki Yamamoto, Fumio Oi, Hideo Yamakado, Hisashi Fukuda, Keiichi Kimura (担当区分：筆頭著者 )

THIN SOLID FILMS ( ELSEVIER SCIENCE SA ) 520 ( 24 ) 7195 - 7199 2012年10月 [査読有り]

Polysilsesquioxanes (PSQs) possessing 3-methacryloxypropyl groups as an organic moiety of the side chain were synthesized by sol-gel condensation copolymerization of the corresponding trialkoxysilanes. The ultra-thin PSQ film with a radical initiator and a cross-linking agent was prepared by a spin-coating method, and the film was cured integrally at low temperatures of less than 120 degrees C through two different kinds of polymeric reactions, which were radical polymerization of vinyl groups and sol-gel condensation polymerization of terminated silanol and alkoxy groups. The obtained PSQ film showed the almost perfect solubilization resistance to acetone, which is a good solvent of PSQ before polymerization. It became clear by atomic force microscopy observation that the surface of the PSQ film was very smooth at a nano-meter level. Furthermore, pentacene-based organic field-effect transistor (OFET) with the PSQ film as a gate insulator showed typical p-channel enhancement mode operation characteristics and therefore the ultra-thin PSQ film has the potential to be applicable for solution-processed OFET systems. (C) 2012 Elsevier B.V. All rights reserved.

Synthesis of Amphiphilic Copolymers Bearing a Spirobenzopyran Moiety at the End Group and Their Photoresponsive Micellar Behaviors in Water

Yoshio Nakahara, Jin Nakamura, Naoya Shirotani, Keiichi Kimura (担当区分：筆頭著者 )

CHEMISTRY LETTERS ( CHEMICAL SOC JAPAN ) 41 ( 10 ) 1142 - 1144 2012年10月 [査読有り]

Novel photoresponsive amphiphilic copolymers, poly{methoxy[oligo(ethylene glycol)] methacrylate-co-styrene}, were synthesized using a spirobenzopyran initiator by atom transfer radical polymerization. The spiropyran and merocyanine forms of the spirobenzopyran moiety at the end group successfully underwent photoisomerization under the conditions of micelle formation, which resulted in a drastic change in micellar properties, e.g., in the assembly state and the hydrophobic environment.

Ion-selective imaging by frictional force microscopy based on ion recognition of ionophores attached to probe tips

Shinpei Kado, Yoshio Nakahara, Keiichi Kimura

ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY ( AMER CHEMICAL SOC ) 244 2012年08月 [査読有り]

Self-assembly of benzo-18-crown-6/crowned-spirobenzopyran copolymers in water and controlled release of entrapped organic dyes by photoirradiation

Yoshio Nakahara, Yuki Okazaki, Keiichi Kimura

ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY ( AMER CHEMICAL SOC ) 244 2012年08月 [査読有り]

Investigation of polysilsesquioxane as a gate dielectric material for organic field-effect transistors

M. Kawamura, Yoshio Nakahara, Mitsuhiro Ohse, Maki Kumei, K. Uno, Hidefumi Sakamoto, Keiichi Kimura, Ichiro Tanaka

APPLIED PHYSICS LETTERS ( AMER INST PHYSICS ) 101 ( 5 ) 2012年07月 [査読有り]

We fabricated pentacene field-effect transistors using polysilsesquioxane (PSQ) as a gate dielectric material that can be cured at sufficiently low temperatures for low cost plastic substrates. The surface roughness of the PSQ films were reduced by the introduction of 3-methacryloxypropyl groups, and their surface energy was controlled to match with that of the pentacene layers by the introduction of phenyl groups. Consequently, the carrier mobility was improved by two orders of magnitude and reached 0.38 cm(2) V-1 s(-1). (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4742891]

Ultra-High-Sensitive Extraction-Photometric Determination of Sodium Ion Using Flow Injection Analysis with a Chromogenic Calix[4]arene Derivative and a Laser Interferometric Photothermal Detector

Daisuke Tsuda, Yoshio Nakahara, Koji Machitani, Masato Kannaka, Eiji Takahashi, Keiichi Kimurar

ANALYTICAL CHEMISTRY ( AMER CHEMICAL SOC ) 84 ( 8 ) 3710 - 3715 2012年04月 [査読有り]

A novel flow injection analysis (FIA) system for ultra-high-sensitive determination of Na+, which involves laser interferometric photothermal equipment as the detector, was designed using a proton-dissociable chromogenic calix[4]arene derivative with a dinitrophenol moiety as the extraction-photometric reagent. The chromogenic calix[4]arene derivative showed an excellent extractability toward Na+, which reflected the cation-complexing property of the tetraethyl ester derivative of calix[4]arene. As the calibration graph of the Na+ concentration could be successfully obtained at the nanomolar level by this method, the proposed FIA system was found to be promising for highly sensitive determination of Na+ in very dilute samples such as supply water and cooling water in power plants.

Potassium-ion-selective sensing based on selective reflection of cholesteric liquid crystal membranes

Shinpei Kado, Yuuhei Takeshima, Yoshio Nakahara, Keiichi Kimura

JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY ( SPRINGER ) 72 ( 1-2 ) 227 - 232 2012年02月 [査読有り]

It is well-known that cholesteric liquid crystals have an optical property, selective reflection, due to changes in the pitch of their helical structure. This unique property of cholesteric liquid crystals can be used to attain a visual sensing system showing color changes as the detection signal. In this paper, we report a visual sensing membrane comprising cholesteric liquid crystals, in which a 15-crown-5 derivative was incorporated as ion recognizing sites, for K+ in aqueous solution. The resulting CLC membrane showed a shift of the reflection peak sensitive to K+ in water. We have also designed polymer-dispersed liquid crystal membranes that showed ion-selective reflection peak shifts with improved response time.

Potassium-ion-selective sensing based on selective reflection of cholesteric liquid crystal membranes

Shinpei Kado, Yuuhei Takeshima, Yoshio Nakahara, Keiichi Kimura

Journal of Inclusion Phenomena and Macrocyclic Chemistry 72 ( 1-2 ) 227 - 232 2012年02月 [査読有り]

It is well-known that cholesteric liquid crystals have an optical property, selective reflection, due to changes in the pitch of their helical structure. This unique property of cholesteric liquid crystals can be used to attain a visual sensing system showing color changes as the detection signal. In this paper, we report a visual sensing membrane comprising cholesteric liquid crystals, in which a 15-crown-5 derivative was incorporated as ion recognizing sites, for K+ in aqueous solution. The resulting CLC membrane showed a shift of the reflection peak sensitive to K+ in water. We have also designed polymer-dispersed liquid crystal membranes that showed ion-selective reflection peak shifts with improved response time. © 2011 Springer-Verlag.

Two-Dimensional Nanoscale Imaging of Sugar Distribution Using AFM Force Sensing with Probe Modified by Concanavalin A

Inoue Shigeto, Nakahara Yoshio, Kado Shinpei, Tanaka Mitsuo, Kimura Keiichi

Journal of Surface Analysis ( 一般社団法人表面分析研究会 ) 18 ( 3 ) 164 - 173 2012年

We have recently realized the two-dimensional visualization of a oligoethyleneglycol (OEG)/mannose (Man)-terminated pattern surface by performing AFM force measurements using a concanavalin A (ConA)-modified AFM tip. To extend the visualization technique, various types of patterned surfaces with localized sugar chains were fabricated by lithography and their two-dimensional visualizations were challenged in a phosphate-buffered saline solution by AFM force measurements using a ConA-modified AFM tip in this study. The adhesion force based on the interaction of ConA with Man was much larger than that based on the interaction of ConA with phosphorylcholine or galactose. The spatial resolution of this method was evaluated using a nanopatterned surface fabricated using silica nanoparticles. Man-terminated regions were clearly distinguishable from OEG-terminated regions on a nanometer scale.

Self-assembling phenomena of benzo-18-crown-6/crowned-spirobenzopyran copolymers in aqueous solution and controlled release of entrapped organic dyes using external stimuli

Yoshio Nakahara, Yuki Okazaki, Keiichi Kimura (担当区分：筆頭著者 )

SOFT MATTER ( ROYAL SOC CHEMISTRY ) 8 ( 11 ) 3192 - 3199 2012年 [査読有り]

A novel amphiphilic vinyl copolymer incorporating benzo-18-crown-6 (BC) and crowned spirobenzopyran (cSP) in the side chain [poly(BC-co-cSP)] was synthesized by free radical copolymerization. The spectroscopic measurements made it clear that poly(BC-co-cSP) forms a micelle in water and that its cSP moiety can bind a metal ion in the micelle. Photochromism based on the spirobenzopyran moiety was successfully observed even under conditions of micelle formation. These results indicate that two external stimuli, metal ions and light, can cause significant changes in the assembly state and physical properties of poly(BC-co-cSP). Release behaviors of encapsulated organic dyes from polymeric micelles consisting of poly(BC-co-cSP) were investigated in Tris-HCl buffer solution (pH 7.4) before and after addition of external stimuli. As a result, it was shown that the performances were largely affected by metal-ion addition and photoirradiation. Thus, controlled release of organic dyes from polymeric micelles was realized using a combination of UV-light and visible-light irradiation in water containing BaCl2.

Effect of photoirradiation on chromatographic separation of alkali metal ions using crowned-spirobenzopyran-immobilized silica

Yoshio Nakahara, Yuki Yamaguchi, Hitoshi Iwamoto, Hidefumi Sakamato, Keiichi Kimura (担当区分：筆頭著者 )

ANALYTICAL METHODS ( ROYAL SOC CHEMISTRY ) 4 ( 12 ) 4025 - 4029 2012年 [査読有り]

We successfully developed a novel photocontrollable chromatographic system for separation of alkali metal ions. Based on the finding that the metal-ion complexation of spirobenzopyran derivatives bearing a crown ether moiety, which we call crowned spirobenzopyran, can be drastically changed by photoirradiation, crowned spirobenzopyrans were immobilized covalently onto silica gels for stationary phases of ion chromatography. Under dark or UV-light irradiation conditions, a marked separation between Li+ and K+ was attained by silica gels modified chemically with crowned spirobenzopyran bearing an 18-crown-6 ring. On the other hand, no significant separation between the two metal ions was found under visible-light irradiation conditions. This result originates from the fact that the K+-complexing ability of crowned-spirobenzopyran-immobilized silica is switched by photoisomerization of the spirobenzopyran moiety from its merocyanine form to spiropyran form. Furthermore, computer simulations of separation of alkali metal ions by crowned spirobenzopyrans in the silica phase were conducted using molecular dynamics calculations.

AFM Observation of Stimuli-Responsive Stretching Behavior for Spirobenzopyran/Crown-Ether Copolymer

Shinpei Kado, Kunika Uehara, Yoshio Nakahara, Keiichi Kimura

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN ) 84 ( 4 ) 422 - 426 2011年04月 [査読有り]

We have observed stretching behavior of a stimuli-responsive polymer chain bearing two functional groups, spirobenzopyran (SP) and crown ether (CR), at the side chain (SP/CR copolymer) by atomic force microscopy (AFM). The spirobenzopyran side chain can undergo photoisomerization from its electrically neutral spiropyran form to zwitterionic merocyanine by UV irradiation. The crown ether side chain can complex with metal ions. These reactions in the side chains would cause changes in their geometric structure and/or physical properties, resulting in the enhanced bifunctionality of SP/CR copolymer based on their stimuli-responsive ability. In this study, SP/CR copolymer, which was adsorbed on mica substrate, was stretched by AFM tip, when external stimuli (i.e., photoirradiation or metal ion addition) were applied. The force-extension curves of SP/CR copolymer were then analyzed by curve fitting based on a theoretical model of polymer chain elasticity to elucidate the external-stimuli effect on the polymer stretching behavior at the single molecule level.

Alkali Metal Ion Sensing Using Absorbance Changes Based on Aggregation of Silica Nanoparticles Modified Chemically with Crown Ethers

Yoshio Nakahara, Takafumi Hayashi, Haruna Kawa, Keiichi Kimura (担当区分：筆頭著者 )

CHEMISTRY LETTERS ( CHEMICAL SOC JAPAN ) 40 ( 4 ) 348 - 350 2011年04月 [査読有り]

Crown-ether-modified silica nanoparticles (Crown SNPs) were successfully prepared by simple chemical modifications of silica nanoparticles. The organic moiety introduced into silica nanoparticles was characterized by solid-state C-13 NMR and elemental analysis. No morphological damage of silica nanoparticles was recognized according to SEM observation. When an alkali metal salt was added to a solution containing Crown-SNPs, the absorbance changes, whose extent was dependent on the kind and the concentration of a metal ion, were observed.

Quantitative H-1 NMR analysis of reacted silanol groups in silica nanoparticles chemically modified with monochlorosilanes

Yoshio Nakahara, Tsutomu Takeuchi, Shoutaro Yokoyama, Keiichi Kimura (担当区分：筆頭著者 )

SURFACE AND INTERFACE ANALYSIS ( WILEY-BLACKWELL ) 43 ( 4 ) 809 - 815 2011年04月 [査読有り]

Quantitative analysis of reacted silanol groups in silica nanoparticles modified chemically with monochlorosilanes was performed by H-1 NMR after treatment with cesium fluoride. Silica nanoparticles were modified chemically by the reaction between the silanol groups and monochlorosilanes, and the structure of the organic moiety anchored onto the silica surface was confirmed with solid-state C-13 NMR. As monochlorosilanes react with silanol groups at 1:1 ratio unlike di-or trichlorosilanes, the number of the silanes introduced into silica nanoparticles equals that of reacted silanol groups. Organically modified silica nanoparticles were dissolved using cesium fluoride, and the amount of the soluble organic compounds originated from the introduced silanes was determined by a H-1 NMR internal standard method using pyrene as the reference. Those values determined by H-1 NMR were in good agreement with those determined by elemental analysis. Thus, the number of reacted silanol groups per one particle was calculated on the basis of the results obtained by the H-1 NMR method, and the values were highly dependent on the steric structure of the introduced silanes. Copyright (C) 2010 John Wiley & Sons, Ltd.

Synthesis of Novel Photochromic Calix[4]arene Ligand Bearing a Spirobenzopyran and Three Ethyl-Ester Moieties and Photocontrol of Its Alkali Metal Ion Extractability

Koji Machitani, Megumi Saeda, Yoshio Nakahara, Keiichi Kimura

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN ) 83 ( 9 ) 1107 - 1112 2010年09月 [査読有り]

A novel photochromic calix[4]arene ligand bearing a spirobenzopyran and three ethyl-ester moieties (compound 1) was synthesized, and photocontrol of its alkali metal ion extractability was studied. In the dark, compound 1 showed the largest changes of absorption spectra for Na+ among alkali metal ions. When Na+ was gradually added to the solution of compound 1, its complexation behavior was evaluated by H-1 NMR, which suggests that Na+ was taken into the cavity formed by four carbonyl oxygens and four ether oxygens, and that compound 1 formed a 1:1 complex with Na+. The proton signals originating from the spirobenzopyran moiety were slightly changed by metal-ion complexation. This means that the spirobenzopyran moiety was not very close to Na+ under dark conditions. Liquid liquid extraction experiments with alkali metal ion using compound 1 made it clear that the extractability of Na+ was enhanced under UV-light irradiation, compared with that under visible-light irradiation. This suggests that the electrostatic interaction between a phenolate anion of the merocyanine moiety generated by UV-light irradiation and Na+ promotes the extractability to some extent.

Morphological Changes in Vesicles and Release of an Encapsulated Compound Triggered by a Photoresponsive Malachite Green Leuconitrile Derivative

Ryoko M. Uda, Eri Hiraishi, Ryo Ohnishi, Yoshio Nakahara, Keiichi Kimura

LANGMUIR ( AMER CHEMICAL SOC ) 26 ( 8 ) 5444 - 5450 2010年04月 [査読有り]

Photoinduced morphological changes in phosphatidylcholine vesicles are triggered by a Malachite Green leuconitrile derivative dissolved in the lipidic membrane, and are observed at Malachite Green derivative/lipid ratios < 5 mol%. This Malachite Green derivative is a photoresponsive compound that undergoes ionization to afford a positive charge on the molecule by UV irradiation. The Malachite Green derivative exhibits amphiphilicity when ionized photochemically, whereas it behaves as a lipophilic compound under dark conditions. Cryo-transmission electron microscopy was used to determine vesicle morphology. The effects of the Malachite Green derivative on vesicles were studied by dynamic light scattering and fluorescence resonance energy transfer. Irradiation of vesicles containing the Malachite Green derivative induces nonspherical vesicle morphology. fusion of vesicles, and membrane solubilization, depending on conditions. Furthermore, irradiation of the Malachite Green derivative induces the release of a vesicle-encapsulated compound.

A Novel Method to Prepare Polysilsesquioxane Nanoparticles Possessing Bromoalkyl Groups

Yoshio Nakahara, Chenghuan Ma, Hiroyuki Yamamoto, Fumio Oi, Keiichi Kimura (担当区分：筆頭著者 )

CHEMISTRY LETTERS ( CHEMICAL SOC JAPAN ) 38 ( 9 ) 876 - 877 2009年09月 [査読有り]

Photochemical Modulation of Europium Ion Fluorescence Using a Tetraazamacrocyclic Derivative Bearing a Spirobenzopyran and Three Carboxymethyl Moieties

Koji Machitani, Yoshio Nakahara, Keiichi Kimura

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN ) 82 ( 4 ) 472 - 474 2009年04月 [査読有り]

Application of Gold Nanoparticles to Spectrophotometric Sensing of Hydrophilic Anions Based on Molecular Recognition by Urea Derivative

Shinpei Kado, Ayumi Furui, Yu Akiyama, Yoshio Nakahara, Keiichi Kimura

ANALYTICAL SCIENCES ( JAPAN SOC ANALYTICAL CHEMISTRY ) 25 ( 2 ) 261 - 265 2009年02月 [査読有り]

We have prepared gold nanoparticles (GNPs) modified with a thiol compound that possesses a phenylurea moiety for the spectrophotometric sensing of hydrophilic anions, such as dihydrogen phosphate, based on changes in the surface plasmon absorption of the GNP. We examined the spectral change of phenylurea-modified GNP in dichloromethane upon the addition of various anions as tetrabutylammonium salts to the Solution. The GNP showed increasing plasmon intensity with the concentration of dihydrogen phosphate. For a control experiment with an inactive hexanethiolate-modified GNP, such an ion-selective change in the plasmon band was not observed. Furthermore, in order to realize the spectrophotometric detection of hydrophilic anions in water using GNP with the urea functionality, we attempted to prepare bifunctional GNP modified with both the phenylurea derivative and a water-soluble thiol (e.g., L-Cysteine). The resulting bifunctional GNP showed anion-selective changes in the plasmon band accompanied by increasing absorbance at a longer wavelength due to GNPs aggregation.

Ion-selective Imaging by Atomic Force Microscopy with a Crown-ether-modified Tip

Shinpei Kado, Hitoshi Yano, Yoshio Nakahara, Keiichi Kimura

CHEMISTRY LETTERS ( CHEMICAL SOC JAPAN ) 38 ( 1 ) 58 - 59 2009年01月 [査読有り]

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