論文 - 會澤 純雄
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Nanoscale chirality generated in zinc(II) orthophosphate clusters: evidence by vibrational circular dichroism
Sumio Aisawa, Nami Horiguchi, Chika Chida, Jing Sang, Hidetoshi Hirahara, Akihiko Yamagishi and Hisako Sato
Nanoscale ( The Royal Society of Chemistry ) 16 20589 - 20595 2024年10月 [査読有り]
国際的学術誌 共著・分担
Layered zinc(II) hydroxides (LZH) intercalating the deprotonated forms of R-(−) or S-(+)-1,1’-binaphthyl-2,2’-diyl hydrogenphosphate (denoted as R- or S-BNDHPH, respectively) were prepared from Zn(NO3)2 atpH 5 and 60 °C by the mixing method. The obtained hybrid compounds (denoted as R- or S-BNDHP−/LZH, respectively) were heated from room temperature up to 800 °C under nitrogen atmosphere. According to the thermal gravimetric/differential thermal analysis measurements, hydroxyl groups were dehydrated at 270–400 °C, followed by the decomposition of organic components at 420–600 °C. X-ray diffraction patterns and scanning electron microscopy images indicated that the final products were a mixture of α-Zn3(PO4)2, ZnO crystals and non-crystalline zinc(II) orthophosphates. Vibrational circular dichroism (VCD) spectra were recorded before and after calcination. Before calcination, R- or S-BNDHP−/LZH exhibited VCD peaks assigned to intercalated R- or S-BNDHP−. The calcined products exhibited several VCD peaks in the range of 900–1200 cm−1, maintaining the mirror-image relationship between R-BNDHP−/LZH and S-BNDHP−/LZH used as starting materials. The observed peaks were assigned to the PvO (symmetric), –POO−, and PvO (asymmetric) stretching vibrations of the PO43− groups. According to theoretical simulations, the observed VCD activity can be rationalised in terms of vibrational coupling between two PO43− groups in a generated chiral zinc(II) orthophosphate cluster.
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Electrical corrosion behavior and erosion mechanism of conductive hard films during current-carrying friction
Mingchong Lu, Jiahua Zhang, Peng Zhang, Qiwei Wang, Jing Sang, Hidetoshi Hirahara, Sumio Aisawa, Dexin Chen
Diamond and Related Materials 153 2025年01月 [査読有り]
学術誌 共著・分担
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Electrical corrosion behavior and erosion mechanism of conductive hard films during current-carrying friction
Mingchong Lu, Jiahua Zhang, Peng Zhang, Qiwei Wang, Jing Sang, Hidetoshi Hirahara, Sumio Aisawa , Dexin Chen
Diamond and Related Materials 153 112018 2025年01月 [査読有り]
学術誌 共著・分担
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Hisako Sato, Sumio Aisawa, Akihiko Yamagishi
Clay Science ( The Clay Science Society of Japan ) 28 ( 1-2 ) 1 - 9 2024年07月 [査読有り]
学会誌 共著・分担
This review describes the application of solid-state vibrational circular dichroism spectroscopy (denoted as SD-VCD) to the intercalation compounds of layered double hydroxides (LDH’s). The hybrid compounds of chiral molecules and LDH are chosen as a main target. SD-VCD is employed to probe the conformation of an intercalated amino acid. Intermolecular interactions are studied from the VCD spectra on LDH samples co-adsorbing an amino acid and tartaric acid. Notably the enhancement of VCD signals occurs to provide evidence for the stereoselective interactions between the intercalated species. As a final goal, the analysis of a model drug tablet containing LDH is described by means of the microscopic scanning VCD method.
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Catalytic mechanism of Co-containing layered double hydroxide (Co-LDH) as a precursor in carbon nanotube (CNT) synthesis
Chika Chida, Sumio Aisawa, Kei Yokoyama, Riku Kumagai, Jing Sang, Hidetoshi Hirahara, Hiroe Kimura, Don N Futaba
Chemistry Letters ( Oxford University Press ) 53 2024年03月 [査読有り]
学会誌 共著・分担
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COPRECIPITATION OF BORON WITH NICKEL(II) HYDROXIDES IN WASTEWATER
Sumio Aisawa, Masatoshi Takahashi, Tooru Abe, Chika Chida, Hidetoshi Hirahara, Eiichi Narita
Clay Science ( 日本粘土学会 ) 27 ( 3-4 ) 33 - 39 2023年12月 [査読有り]
学会誌 共著・分担
In this work, the removal of boron (B) in wastewater was investigated by the coprecipitation method using bivalent metal ion as a precipitant. From the preliminary experiments conducted under the fundamental conditions, the removal percentage (coprecipitation degree) of B was found to be quite different depend on the kind of metal ions used, and it became the highest as 95.9% when Ni2+ ion was adopted. Also, the residual B concentration was under the limited value (10 mg/L) of the regulation for wastewater. Then, the optimum conditions in this case were studied in detail and the result was as follows; Initial B concentration=300 mg/L, Ni2+/B molar ratio=12/1, temperature 25°C and pH 9–10. Comparing with the Ni–Al layered double hydroxide prepared under the same condition, this nickel hydroxide precipitate indicated much higher removal ability for B. The precipitate obtained at the optimum condition was mainly the layered nickel hydroxide coordinating borate ion in the interlayer space, which basal spacing being 0.80 nm. Depending on the conditions, several other precipitates such as nickel hydroxide hydrate (3Ni(OH)2·2H2O) and theophrastite (Ni(OH)2) formed highly accompanying borate ion on their surface or inside. In conclusion, new simple method for the B removal by the coprecipitation using Ni2+ ion at higher pH was proposed in this study.
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Synthesis of phenylalanine and tartaric acid intercalated layered double hydroxide (LDH): Investigation of two kinds of chiral molecules interaction in interlayer space of LDH using solid-state vibrational circular dichroism
Sumio Aisawa, Chika Chida, Honoka Ida, Jing Sang, Hidetoshi Hirahara, Hisako Sato
Applied Clay Science ( Elsevier B.V. ) ( 244 ) 2023年11月 [査読有り]
国際的学術誌 共著・分担
Recently, the applicability of solid-state vibrational circular dichroism (SD-VCD) for the evaluation of organoclay nanohybrids has attracted much attention. Herein, the intercalation of two kinds of chiral molecules, phenylalanine (Phe) and tartaric acid (Tart), into Zn-Al layered double hydroxide (LDH) was carried out by a standard coprecipitation method. The Phe/Tart/LDH was characterized by XRD, FT-IR, TG-DTA, and SD-VCD. The chemical composition and interlayer distance expansion of Phe/Tart/LDH indicated that Phe and Tart were intercalated into the LDH. The VCD and theoretical calculation results showed that Phe and Tart coexisted in the same interlayer space of LDH with the formation of electrostatic interaction and hydrogen bonding between Phe-Tart, LDH-Phe, and LDH-Tart. The results demonstrated the utility of the SD-VCD method for determining the detailed conformation of chiral molecules in the LDH interlayer space.
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Structural, optical, and photocatalytic properties of rare-earth free double-perovskite oxides Ba2Bi3+(Bi5+1-2xSb5+2x)O6
Dayal Chandra Ro, Michiaki Matsukawa, Minami Arakida, Hanako Sakou, Kazuto Hata, Kazume Nishidate, Sumio Aisawa, Hajime Yamamoto, Akiyuki Matsushita
Solid State Communications ( Elsevier Ltd. ) 373–374 2023年09月 [査読有り]
学術誌 共著・分担
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Superhydrophobic coatings by electrodeposition on Mg–Li alloys: Attempt of armor-like Ni patterns to improve the robustness
Hongyuan He, Jiebin Du, Jing Sang, Hidetoshi Hirahara, Sumio Aisawa, Dexin Chen
Materials Chemistry and Physics 304 ( 127902 ) 2023年05月 [査読有り]
国際的学術誌 共著・分担
Due to the fragility of the layered structure, the mechanical properties of superhydrophobic surfaces, particularly wear resistance, are still too poor, limiting the industrial application of protecting magnesium-lithium (LZ91) alloys from corrosion. As a result, we’re testing screen-printed masks to electroplate armor-like Ni columns. Then, using electrodeposition, compact micro/nanometer-sized papillary structured superhydrophobic surfaces are created on Mg–Li alloys, which exhibit good low viscosity, self-cleaning, chemical stability, and excellent corrosion resistance with a 2 order of magnitude decrease in corrosion current density in both corrosive media. Surprisingly, increasing the deposition time causes the dissolution of Cu anode electrodes and the subsequent formation of Cu compounds on the superhydrophobic coating, resulting in the formation of dense needle-like structures on these papillae. Even after the superhydrophobic structures are worn away, the armor-like Ni col- umns reduce the contact angle’s tendency to decrease. This proposed deposition method provides a simple and fast process for protecting the surface of Mg–Li alloys, and the concept of armored Ni patterns may pave the way for future advances in the robustness and application of superhydrophobic coatings.
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Synthesis of Carbon Nanotube using Layered Double Hydroxide with Various Metal Compositions as Catalyst Precursors
Chika Chida, Sumio Aisawa, Riku Kumagai, Jing Sang, Hidetoshi Hirahara, Hiroe Kimura, Don N. Futaba
Chemistry Letters ( The Chemical Society of Japan ) 52 412 - 415 2023年04月 [査読有り]
学会誌 共著・分担
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Enhanced photocatalytic activities under visible light of double-perovskite oxide semiconductor Ba2Tb(Bi, Sb)O6 with mixed-valence
Dayal Chandra Roy, Michiaki Matsukawa, Takanori Yonai, Minami Arakida, Haruka Taniguchi, Kazume Nishidate, Sumio Aisawa, Akiyuki Matsushita, Lin Shiqi
Journal of Materials Science: Materials in Electronics 34 ( 281 ) 2023年01月 [査読有り]
学術誌 共著・分担
In this study, we showed the effect of Sb substitution on lattice structures, physical properties and photocatalytic activities for the double-perovskite oxides with mixed valence. High quality powders of Ba2Tb(Bi1−xSbx)O6 (0.1≤x≤1.0) were successfully synthesized using a citrate pyrolysis approach. Through partial substitution of Sb at Bi site of this compound, it was possible to design oxidative photocatalysts at lower x, and reduction-type ones at higher x. These findings are discussed on the basis of the conduction and valence band edge potentials of a series of Ba2(Tb, Pr)(Bi, Sb)O6 photocatalysts. The Sb substituted sample with the x = 0.6 composition predicted from the machine learning procedure exhibited the highest performance of methylene blue degradation, which is comparable to typical degradation rates for good perovskite catalysts.
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Preparation of hollow nanosphere of 5-fluorouracil/layered double hydroxide and its cellular cytotoxicity
Sumio Aisawa, Jing Sang , Daisuke Suga , Hidetoshi Hirahara , Eiichi Narita
Applied Clay Science ( Elsevier B.V. ) ( 226 ) 2022年09月 [査読有り]
国際的学術誌 共著・分担
We have first prepared the layered double hydroxide (LDH)/carbon nanosphere (CNS) composite by mixing the LDH gel containing methoxide interlayer anion with the CNS template (particle size of 300–700 nm) suspension in methanol at room temperature under ultrasonication. The SEM observation indicates that the CNS core was uniformly covered with the LDH thin film made up by fine plate-like particles to form the composite. Then, the intercalation of anticancer drug, 5-fluorouracil (5-FU), into the LDH interlayer was carried out by the calcinationrehydration reaction and the solid products were analyzed using XRD, FT-IR, SEM, TEM etc. During the calcination process at 500 ◦C for 3 h, the CNS core was removed by combustion and the LDH shell became the hollow LDH oxide nanosphere. In the following rehydration process at 60 ◦C for 24 h, this oxide precursor was reconstructed the hollow LDH nanosphere having the surface of coral-like structure (spontaneously formed LDH particles) incorporating 5-FU anion in the interlayer. Finally, the anticancer drug efficacy in vitro of the products was estimated by using the WST-8 assays in HeLa cell lines. As the result, the hollow nanosphere of the 5-FU/ LDH performed an improvement of drug efficacy compared to the conventional plate-like particle of the 5-FU/LDH as the reference and the naked 5-FU itself at the same 5-FU concentration.
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トリアジンチオール末端オリゴ（2-メチル-2-オキサゾリン）による銅表面の親水化
佐藤久美子,會澤純雄,平原英俊,菊地康昭,成田 榮一
色材協会誌 95 ( 8 ) 229 - 234 2022年08月 [査読有り]
学術誌 共著・分担
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Hisako Sato, Sumio Aisawa, Honoka Ida, Masaru Shimizu, Keisuke Watanabe, Jun Koshoubu, Jun Yoshida, and Izuru Kawamura
Chemistry Letters ( The Chemical Society of Japan ) 51 ( 2 ) 205 - 207 2021年12月 [査読有り]
学会誌 共著・分担
A vibrational circular dichroism (VCD) system with a quantum-cascade laser was used to obtain a two-dimensional image of VCD signals on a pharmaceutical tablet. A KBr disc of a model dosage form was prepared using tartaric acid and phenylalanine as chiral multi-reagents and layered double hydroxides as excipients. VCD spectra were obtained in the range 1500-1700 cm-1 at a 1 mm i.d. spatial resolution. The results demonstrated the utility of the proposed system in quality control during drug manufacturing.
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A kinetic analysis of intercalation of organic sulfate anions into layered double hydroxide using quartz crystal microbalance with layered double hydroxide-immobilized electrode
Sumio AISAWA, Jing SANG, Yuya NITANAI, Hidetoshi HIRAHARA, Eiichi NARITA
Journal of the Ceramic Society of Japan ( 公益社団法人日本セラミックス協会 ) 129 ( 7 ) 470 - 477 2021年07月 [査読有り]
学術誌 共著・分担
To investigate a dynamic intercalation behavior of organic anions into layered double hydroxide (LDH) interlayer by ion-exchange, a quartz crystal microbalance (QCM) with the Mg–Al LDH thin film immobilized gold disc (LDH/QC) electrode has been used. A stable minute LDH film was prepared by using translucent aqueous sol of LDH containing OH− ions and magnesium acetate molecule in the interlayer and immobilized on the gold disc after pretreatment of the surface of the supporting silica electrode with hydrophobic agent. In the kinetic analysis, alkyl sulfates having n-alkyl chain (CnH2n+1, n = 5–12; abbreviated as CnS) were used as guest anions. As the results, the time-dependence on CnS intercalation by ion-exchange with guest OH− ions and magnesium acetate molecules was measured in the cases of CnS (n ≥ 7), and the data of C11S and C12S intercalation were successively analyzed using the rate equation based on the reversible pseud first-order reaction. Finally, the instrumental analyses of the LDH films before and after the intercalation of C12S revealed that the organic anions could be intercalated into the LDH interlayer of the LDH/QC electrode in each aqueous solutions.
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Interfacial Molecular Motion and Chemical Characteristics of Polymer Jointed to Metal by Chemical Bonding
Xueliang Deng, Jing Sang, Sumio Aisawa, Katsuhito Mori , Hidetoshi Hirahara
Journal of the Japan Society of Colour Material 94 ( 6 ) 149 - 157 2021年06月 [査読有り]
学術誌 単著
シリコンゴムとAlが接触方式による放熱材料の熱伝導性，接着剤による接合での熱伝導性，そして界面化学結合により創成したシリコンゴムとAl複合体の化学接合方式による熱伝導特性への影響を評価することによって，ヒートシンクと放熱材料，および放熱材料と熱源の界面の接触熱抵抗の影響を解明している。シリコンゴムとAl複合体の熱伝導特性におよぼすシリコンゴム架橋剤添加量とシリコンゴム厚さの影響について検討した。シリコンゴムとAlの接触方式による熱伝導性と接着剤による接合での熱伝導性，そして分子接合剤により界面化学結合させたシリコンゴムとAl複合体の化学接合方式によって熱伝導特性が異なることを解明し，化学結合を用いて接合したシリコンゴムとAl複合体放熱材料はシリコンゴムとヒートシンク(Al)材料の接触熱抵抗の減少に有効であることを明らかにした。
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Sumio Aisawa, Jing Sang, Ayaka Masubuchi, Hidetoshi Hirahara, Eiichi Narita
Clay Science ( The Clay Science Society of Japan ) 24 ( 2-4 ) 47 - 54 2021年02月 [査読有り]
学術誌 共著・分担
The intercalation behavior of vanillin (VL), one of the most famous flavoring components having aldehyde structure, and its related compounds, m-anise aldehyde (MA) and 2-methoxyphenol (MP), into Mg–Al layered double hydroxide (LDH) has been examined by the calcination-rehydration (reconstruction) method using LDH oxide precursor at 25°C for 24 h. The molar ratio of the organic guest in aqueous solution to Al3+ ion in LDH oxide was set at 1.00 in all the experiments. The solid product was found to incorporate the guest depend on its structure together with hydroxide ion and to show the restorable LDH structure. The amounts of the organic guest intercalated (the guest/Al molar ratio of the solid product) were as follows: VL (0.81)>MP (0.41)>MA (0.18), and the effect of each substituent group of the guests was also discussed. In the case of vanillin isomers, the intercalated amounts were differently in the order; VL (0.81)>ortho-vanillin (0.58)>iso-vanillin (0.35), whereas the intercalated amounts of anise isomers were, on the whole, lower than VL isomers as MA (0.18)>ortho-anise (0.034)>para-anise (0.012). The XRD patterns of the solid products showed that VL was intercalated as a monovalent anion to make bilayer and to keep horizontal orientation for the LDH basal layer, and the others were intercalated to keep parallel orientation in the interlayer. Moreover, the results of the guest deintercalation (release) experiments from the solid products by ion exchange with chloride or carbonate ion revealed that the easier intercalated guest, the more difficult released one from the solid products.
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Structural, physical and photocatalytic properties of mixed-valence double-perovskite Ba2Pr(Bi,Sb)O6 semiconductor synthesized by citrate pyrolysis technique
Arisa Sato, Michiaki Matsukawa, Haruka Taniguchi, Shunsuke Tsuji, Kazume Nishidate, Sumio Aisawa, Akiyuki Matsushita, Kun Zhang
Solid State Sciences ( Elsevier ) 107 106352 2020年07月 [査読有り]
学術誌 共著・分担
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ADSORPTION OF ZEARALENONE ON CLAY AND TREATED CLAY MATERIALS IN AQUEOUS SOLUTIONS
Noriyuki Takahashi, Sumio Aisawa, Hidetoshi Hirahara, Eiichi Narita
Clay Science ( The Clay Science Society of Japan ) 24 23 - 30 2020年06月 [査読有り]
学会誌 共著・分担
First, in order to find suitable evaluation factors of zearalenone (ZEA) adsorption ability of clay and treated clay materials, their specific surface area values obtained from nitrogen and water adsorption isotherms, SA(N2) and SA(H2O), and monolayer adsorption capacities of water and toluene obtained from each adsorption isotherms, Vm(H2O) and Vm(toluene), were measured together with their ZEA adsorption ability. However, any good relationships between the measured values and the ZEA adsorption ability were not recognized here. This result means that the mechanism of ZEA adsorption is complicated depend on the kind of clay. From the water and toluene adsorption isotherms of these adsorbents, the reason of the higher adsorption ability of clays such as magnesium silicate and talc adsorbents was clarified and a certain good relationship between the SA(H2O)/SA(N2) ratio and the ZEA adsorption ability was found for these adsorbents. Next, the acid treatment and heat treatment of the Japanese acid earth, JAE sample, were carried out to develop economically the effective adsorbent for ZEA in aqueous solutions. Consequently, the heat treatment of the JAE sample resulted a dramatic decrease in the values of Vm(H2O) and SA(H2O)/SA(N2) ratio, meaning the higher adsorption ability for ZEA. The ZEA adsorption ability of the HE-K sample heated at 773 K was the largest in all the clay adsorbents except the reference samples.
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Sumio Aisawa, Chie Nakada, Hidetoshi Hirahara, Noriyuki Takahashi, Eiichi Narita
Applied Clay Science 180 2019年11月 [査読有り]
学術誌 共著・分担
In recent years, layered double hydroxide (LDH) well-known as hydrotalcite-like compound has received considerable attention due to its potential technological applications such as antacid, anion-exchangers, stabilizers and reinforcing fillers for synthetic or natural organic polymers. On the other hand, one of polyhydric alcohols, dipentaerythritol (Dpe), is known as a typical component of polyvinyl chloride (PVC) stabilizer. In this study, we attempted the intercalation of Dpe into a carbonated Mg–Al LDH (the Mg–Al/CO3/LDH) interlayer by the thermal reaction using molten guest substance to develop a new effective thermostabilizer for PVC resin. During the thermal reaction at 200–235 °C, the decarboxylation and dehydration of the Mg–Al LDH proceeded and the solid product at 235 °C after 3 h was found to be the most disordered structure, not the Dpe-intercalated LDH. The results of FT-IR, TG-DTA, and chemical analysis exhibited that the solid product was the aggregate of the disordered LDH particles covering with Dpe molecule (Mg–Al LDH-Dpe composite) and a small amount of the Mg–Al/OH/LDH. Next, we prepared the PVC sheet by loading the solid product or various kinds of additives into PVC paste resin with dioctyl phthalate and etc. by molding and subsequently by heating. In the heat-resistance test of the resulted PVC sheets at 180 °C for 2 h, the PVC sheet loaded with the solid product showed the longest heat-resistance in all the cases. It also exhibited the best results in each the hardness and elongation tests of the PVC sheet recovered after the heat-resistance test. Although we could not prepare the Dpe-intercalated LDH, the Mg–Al LDH-Dpe composite exhibiting the expectable ability as thermostabilizer for PVC resin was obtained in this study.