Imai, Hiroaki

写真a

Affiliation

Faculty of Science and Technology, Department of Applied Chemistry (Yagami)

Position

Professor

Related Websites

External Links
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Profile Summary 【 Display / hide 】

  • 材料化学、バイオミネラリゼーション、無機機能材料、自己組織化プロセス

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Career 【 Display / hide 】

  • 1985.04
    -
    1985.11

    日本酸素株式会社開発本部

  • 1985.11
    -
    1987.12

    工業技術院電子技術総合研究所出向

  • 1988.01
    -
    1992.03

    日本酸素株式会社技術本部

  • 1992.04
    -
    1993.03

    日本酸素株式会社電子機材事業本部

  • 1993.04
    -
    1996.03

    慶應義塾大学（理工学部）助手

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Academic Background 【 Display / hide 】

  • 1983.03

    Keio University, Faculty of Engineering, 応用化学科

    University, Graduated

  • 1985.03

    Keio University, Graduate School, Division of Engineering, 応用化学専攻

    Graduate School, Completed, Master's course

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Academic Degrees 【 Display / hide 】

  • 工学　, Keio University, 1990.03

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Books 【 Display / hide 】

  • Synthesis of Structured Spinel Oxide Positive Electrodes to Improve Electrochemical Performance

    Imai H., Next Generation Batteries: Realization of High Energy Density Rechargeable Batteries, 2021.01

    　View Summary

    In this chapter, a novel structural design concept of positive electrodes is shown for improving the electrochemical performance of magnesium rechargeable batteries. Here, two types of structured spinel oxides, such as spinel MgCo2O4 mesocrystals consisting of iso-oriented nanometer-sized subunits and hierarchical porous frameworks of MgMn2O4 with interconnected bimodal pores, are proposed as potential cathode materials. The capacity of the active materials improves with a decrease in the overpotential because the reactivity and the electron and ion conductivities are highly enhanced in the designed architectures of the cathode materials.

  • Ultraviolet (UV) irradiation

    Imai H., Handbook of Sol-Gel Science and Technology: Processing, Characterization and Applications, 2018.07

    　View Summary

    Ultraviolet (UV) photons interact with chemical bonds in systems undergoing sol-gel processing. Generally, UV photons induce electronic excitations in precursors containing organic and inorganic components. In particular, UV irradiation has been used to heat, to create defects, to reduce organics, and to pattern gels. UV-induced densification and crystallization have been observed. Gels containing photo-sensitizers have been studied for patterning applications.

  • Nanoscience Volume 1:Nanostructures through Chemistry

    Yuya Oaki and Hiroaki Imai, The Royal Society of Chemistry, 2013

    Scope: 1-28

  • Mesoscale Chemistry

    Hiroaki Imai, Yuya Oaki, Pan Stanford Publishing. Ltd., 2012

  • 最先端材料システムワンポイントシリーズ「自己組織化と機能材料」

    IMAI HIROAKI, 共立出版, 2012

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Papers 【 Display / hide 】

  • Enhanced and stabilized photoluminescence of perovskite cesium lead bromide nanocubes through ordered assemblies

    Sasaki M., Hashimoto S., Iso Y., Oaki Y., Isobe T., Imai H.

    Nanoscale Advances (Nanoscale Advances)  5 ( 9 ) 2553 - 2557 2023.04

    　View Summary

    This work clarified the effects of self-assembly of perovskite cesium lead bromide (CsPbBr3) nanocubes (NCs) covered with didodecyldimethyl ammonium bromide (DDAB) on photoluminescence (PL) properties. Although the PL intensity of isolated NCs was weakened in the solid state even under inert conditions, the quantum yield of PL (PLQY) and the photostability of DDAB-covered NCs were drastically improved by the formation of two-dimensional (2D) ordered arrays on a substrate. The PLQY of the 2D arrays increased to ca. 60% by initial excitation illumination at 468 nm and was maintained for over 4000 h. The improved PL properties are attributable to the fixation of the surface ligand around the NCs in the specific ordered arrays.

  • Construction of Millimeter-Wide Monolayers of Ordered Nanocubes as a Stain of “Wineglass Tears” Driven by the Marangoni Flow

    Takatsuji Y., Matsumoto R., Sazaki G., Oaki Y., Imai H.

    Langmuir (Langmuir)  39 ( 11 ) 4091 - 4099 2023.03

    ISSN  07437463

    　View Summary

    We constructed millimeter-wide monolayers consisting of tetragonally ordered BaTiO3 (BT) nanocubes through the liquid film formation caused by the Marangoni flow in a toluene-hexane binary liquid containing oleic acid. A thin liquid film containing BT nanocubes was overspread on a standing silicon substrate through the condensation of toluene at the advancing front after the preferential evaporation of hexane. Then, the oscillatory droplet formation like “wineglass tears” occurred on the substrate. Finally, two-dimensionally ordered BT nanocubes were observed as a stain of “wineglass tears” on the substrate after the liquid film receded through evaporation. The presence of a thin liquid film in the binary system is essential for the production of millimeter-wide monolayers on the substrate because multilayer deposition occurs without the formation of a thin liquid film in monocomponent systems. We improved the regularity of the ordered arrays of nanocubes by adjusting the liquid component and evaporation conditions.

  • Stimuli-Responsive Sponge for Imaging and Measuring Weak Compression Stresses

    Ono N., Seishima R., Okabayashi K., Imai H., Fujii S., Oaki Y.

    Advanced Science (Advanced Science)  10 ( 3 )  2023.01

    　View Summary

    Imaging and measuring compression stresses secure a safe and healthy life. Compression stresses in kPa range are not easily detected by conventional mechanoresponsive materials because microscopic molecular motion of the chromophores is not induced by such weak stresses. Moreover, imaging of the stress distribution is not achieved so far. The present study shows a sponge device combining two stimuli-responsive materials, a capsule releasing interior liquid and color-changing polymer in responses to compression stress and chemical stimulus, respectively. The stimuli-responsive capsule is dispersed on a melamine sponge comprised of the fibers with coating the layered polydiacetylene (PDA). The application of weak compression stresses induces collapse of the capsules, outflow of the interior liquid, and subsequent irreversible color change of PDA. The cascading response in the sponge device colorimetrically enables imaging of the distribution and measuring the strength of the compression stresses in kPa range. Furthermore, the device demonstrates imaging and measuring unknown weak compression stresses applied by the irregular-shaped objects. A couple of clinical issues in surgical operation of intestine are studied using the stress-imaging sponge device. The device and its design strategy can be applied to stress imaging in a variety of fields.

  • Fabrication process development and basic evaluation of eggshell-based column packing material for reversed-phase preparative separation

    Yoshii T., Sakama A., Kanamori K., Nakanishi K., Imai H., Citterio D., Hiruta Y.

    Journal of Chromatography A (Journal of Chromatography A)  1688 2023.01

    ISSN  00219673

    　View Summary

    Purification of basic drugs in reversed-phase mode is often difficult, mainly due to adsorption of positively charged compounds to the silica gel-based stationary phase. Since this adsorption can be suppressed under alkaline condition, columns with alkali-resistance are required. In addition, compounds with acid-sensitive structures are sometimes degraded during separation on silica gel-based columns which exhibit acidity due to their surface structure. We prepared an alkali-resistant reversed-phase packing material, Eggshell-PMAcO based on eggshells modified with an amphiphilic copolymer, poly(maleic acid-alt-1-octadecene) (PMAcO). The height equivalent to a theoretical plate (HETP) of the Eggshell-PMAcO column was improved by surface treatment with ammonium acetate buffer (900 mM, pH = 3.7), which is an inexpensive reagent, and the retention behavior for hydrophobic compounds was compared to a typical ODS column based on silica gel, resulting in sufficient selectivity of the eggshell-based column for hydrophobic compounds, as indicated by the ratio of retention factors of pentylbenzene and butylbenzene (Eggshell-PMAcO column: 1.55, ODS column: 1.65). Column temperature-dependent retention behavior of naphthalene was investigated in the temperature range from 25 °C to 45 °C, followed by the calculation of thermodynamic parameters. There was little difference in the standard molar enthalpy (Eggshell-PMAcO: −19.6 kJ/mol, ODS: −21.7 kJ/mol). The absolute value of the standard free Gibbs energy for the Eggshell-PMAcO column was much smaller than that of the ODS column (Eggshell-PMAcO: −0.284 kJ/mol, ODS: −13.0 kJ/mol), indicating that the Eggshell-PMAcO column had a weaker retention strength for naphthalene than the ODS column mainly due to the large difference in the standard molar entropy (Eggshell-PMAcO: −64.9 J/mol K, ODS column: −29.2 J/mol K). The retention capacities for imipramine under neutral (water/methanol) and alkaline (0.1% triethylamine water/methanol) conditions were 0.2 mg and 5 mg, respectively, based on injection mass-dependent HETP, retention factor and symmetry factor. Finally, the prepared column was applied to the purification of a building block for nucleic acid drugs. This study demonstrated that reversed-phase columns, which can be fabricated from eggshells and an amphiphilic copolymer in an inexpensive and eco-friendly way, have the ability to purify basic compounds and acid-sensitive compounds.

  • A highly sensitive friction-imaging device based on cascading stimuli responsiveness

    Shioda N., Kobayashi R., Katsura S., Imai H., Fujii S., Oaki Y.

    Materials Horizons (Materials Horizons)   2023

    ISSN  20516347

    　View Summary

    Imaging and measurement of friction forces are required in a variety of fields. If the friction forces originating from the motions of professionals are quantitatively analyzed, the data can be applied to a motion-copying system by a robot. However, weak friction forces have not been visualized and quantified using conventional sensing materials and devices because of their low sensitivity. Here we present a highly sensitive friction-imaging device based on the cascading responses of stimuli-responsive materials, namely polydiacetylene (PDA) and dry liquid (DL). Weak friction forces disrupt the DL, which is composed of liquid droplets surrounded by solid particles. The outflowing liquid under chemical stress changes the color of PDA. The cascading responses enable colorimetric imaging and measurement of weak friction forces in the range of 0.006-0.080 N. Furthermore, the device visualizes the force distribution of handwriting in calligraphy depending on the individual characteristics of an expert, a practician, and a beginner. A high-sensitivity friction-imaging device can be used to understand various motions.

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Papers, etc., Registered in KOARA 【 Display / hide 】

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Presentations 【 Display / hide 】

  • ゾルゲル法による多孔質スピネル型MgMn2O4の合成およびマグネシウム二次電池への応用

    Hiroaki Imai

    The Ceramic Society of Japan Annual Meeting 2019 (Kogakuin University (Shinjuku Campus)) , 

    2019.03
    , 

    Oral presentation (general)

  • ドライおよびウェットな低温環境におけるカルサイトナノ結晶の開裂と粒成長

    Hiroaki Imai

    The Ceramic Society of Japan Annual Meeting 2019 (Kogakuin University (Shinjuku Campus)) , 

    2019.03
    , 

    Oral presentation (general)

  • カルサイトナノロッドの単層集積によるナノスケールパターンの形成

    Hiroaki Imai

    The Ceramic Society of Japan Annual Meeting 2019 (Kogakuin University (Shinjuku Campus)) , 

    2019.03
    , 

    Oral presentation (general)

  • Fe3O4ナノキューブ単層配列体の作製およびその磁気特性の評価

    Hiroaki Imai

    The Ceramic Society of Japan Annual Meeting 2019 (Kogakuin University (Shinjuku Campus)) , 

    2019.03
    , 

    Oral presentation (general)

  • 炭酸含有水酸アパタイトナノ粒子の合成とマクロ造形への応用

    Hiroaki Imai

    The Ceramic Society of Japan Annual Meeting 2019 (Kogakuin University (Shinjuku Campus)) , 

    2019.03
    , 

    Oral presentation (general)

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

  • 大規模かつ階層的なメソクリスタル構造の構築と無機・有機融合機能の開拓

    2021.04
    -
    2025.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Principal investigator

  • デザインされた異方性ナノブロックによる秩序配列マテリアルの構築と機能開拓

    2016.04
    -
    2020.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A) , Principal investigator

  • Clarification of crystal growth through oriented attachment and its application for development of nanomaterials

    2015.04
    -
    2018.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, Principal investigator

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Works 【 Display / hide 】

  • 実験化学講座「無機化合物」

    IMAI HIROAKI

    2005.03
    -
    Present
    , 

    Other, Joint

    　View Details

    固体化学・無機材料化学の研究・教育に重要な各種の実験技術の解説書。

  • セラミックス大学

    IMAI HIROAKI

    2000.05
    -
    2006.10
    , 

    Other, Joint

    　View Details

    年間7〜8回の講義を通して、セラミックスの基礎と応用を社会人、大学生を問わず分かりやすく解説する教育講座の企画および講師を担当。

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Awards 【 Display / hide 】

  • 日本結晶成長学会第32回論文賞

    今井宏明, 2015.10, 日本結晶成長学会, メソ結晶におけるねじれ形態発現機構の解明とその制御

  • 第 68 回（平成 25 年度）日本セラミックス協会賞学術賞

    今井宏明, 2013.11, 公益社団法人日本セラミックス協会, バイオミネラルに着想を得たセラミックス合成プロセスの深化と応用

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Courses Taught 【 Display / hide 】

  • SEMINAR IN APPLIED CHEMISTRY

    2024

  • SCIENCE OF SELF-ASSEMBLY

    2024

  • NANO SCALE SCIENCE JOINT SEMINAR

    2024

  • MATERIAL DESIGN SCIENCE JOINT SEMINAR

    2024

  • LABORATORIES IN APPLIED CHEMISTRY C

    2024

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Social Activities 【 Display / hide 】

  • 全国高校化学グランプリ2012・2次選考特別講演・公益社団法人日本化学会

    2012.08

    　View Summary

    参加者：中高生約80名

  • ひらめき☆ときめきサイエンス～ようこそ大学の研究室へ～KAKENHI:「生き物による結晶づくりを学び・まねしよう」講義と実験

    2011.08

    　View Summary

    参加者：中高生19名
    於：慶応義塾大学矢上キャンパス

  • 全国高校化学グランプリ2011 2次選考特別講演

    2011.08

    　View Summary

    主催：「夢・化学-21」委員会
    参加者：中高生約80名
    於：慶應義塾大学日吉・矢上キャンパス

  • 独立行政法人産業技術総合研究所

    2008.05
    -
    Present

  • 独立行政法人物質・材料研究機構

    2001.05
    -
    2005.03

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Memberships in Academic Societies 【 Display / hide 】

  • 日本セラミックス協会編集委員会, 

    2010.04
    -
    2018.06

  • 日本セラミックス協会行事企画委員会, 

    2007.04
    -
    2009.03

  • 日本化学会欧文誌編集員会, 

    2005.04
    -
    2010.03

  • 日本ゾルゲル学会, 

    2003.07
    -
    Present

  • 日本結晶成長学会, 

    2000.04
    -
    Present

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Committee Experiences 【 Display / hide 】

  • 2018.06
    -
    Present

    運営委員会委員長, 日本セラミックス協会

  • 2010.04
    -
    2018.06

    Editor, 日本セラミックス協会編集委員会

  • 2008.05
    -
    2010.04

    客員研究官, 独立行政法人産業技術総合研究所

  • 2007.04
    -
    2009.03

    Committee Chair, 日本セラミックス協会行事企画委員会

  • 2005.04
    -
    2010.03

    Editor, 日本化学会欧文誌編集員会

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