Updated on 2026/08/05

写真a

 
Kato Riki
 
Organization
Research Institute for Interdisciplinary Science Special-Appointment Assistant Professor
Position
Special-Appointment Assistant Professor
External link

Degree

  • 博士（工学）

Research Interests

  • ナノロッド

  • 自己組織化

  • バイオミネラリゼーション

  • 有機無機複合材料

  • ゲル

  • 構造色

  • ナノシート

  • コロイド液晶

  • ナノファイバー

  • コロイド

Research Areas

  • Nanotechnology/Materials / Functional solid state chemistry

  • Nanotechnology/Materials / Nanometer-scale chemistry

Education

  • Fukuoka Institute of Technology   工学研究科   物質生産システム工学専攻

    2018.4 - 2021.3

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  • Fukuoka Institute of Technology   工学研究科   生命環境化学専攻

    2016.4 - 2018.3

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  • Fukuoka Institute of Technology   工学部   生命環境科学科

    2012.4 - 2016.3

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Research History

  • Okayama University   The Research Institute for Interdisciplinary Science

    2024.4

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  • The University of Tokyo   The Graduate School of Engineering Department of Chemistry and Biotechnology   Postdoctoral Fellow

    2021.4 - 2024.3

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Papers

  • Electrochemical Synthesis of Benzo[ b ]Phosphole Oxides via Dehydrogenative Annulation Using 1,4‐Diazabicyclo [2.2.2]Octane as a Mediator

    Koichi Mitsudo, Sakura Kinjo, Yasuyuki Okumura, Eisuke Sato, Riki Kato, Yuta Nishina, Seiji Suga

    ChemElectroChem   13 ( 8 )   2026.4

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    Publishing type：Research paper (scientific journal)   Publisher：Wiley  

    The electrochemical intermolecular annulation of diarylphosphine oxides with alkynes for the synthesis of benzo[ b ]phosphole oxides has been reported. The reaction proceeded under transition‐metal‐ and oxidant‐free conditions via indirect electrolysis, using 1,4‐diazabicyclo[2.2.2]octane as a mediator. High‐surface‐area carbon electrodes, such as carbon felt and reticulated vitreous carbon, are essential for this reaction. Several diarylphosphine oxides and alkynes were applied to electrochemical annulation, and the corresponding benzo[ b ]phosphole oxides were obtained. Mechanistic studies suggested that the reaction proceeds via radical intermediates generated through multiple pathways.

    DOI： 10.1002/celc.70175

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    Other Link： https://chemistry-europe.onlinelibrary.wiley.com/doi/full-xml/10.1002/celc.70175

  • Liquid‐Crystalline Biomineral Nanofibers: 1D Inorganic Materials with a High Aspect Ratio and Anisotropic Self‐Assembled Nanocomposites

    Takahiro Mikami, Riki Kato, Nobuyoshi Miyamoto, Takashi Kato

    Advanced Materials   2026.1

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1002/adma.202514457

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  • Hidden ordered structure of clay nanosheets in binary colloids of niobate and clay nanosheets disclosed by small-angle neutron scattering. International journal

    Teruyuki Nakato, Riki Kato, Wataru Ishitobi, Emiko Mouri, Hiroki Iwase, Nobuyoshi Miyamoto

    Soft matter   2025.12

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    Language：English   Publishing type：Research paper (scientific journal)  

    Binary colloids of two different nanosheet species are promising systems for novel integrated materials because of their multicomponent and multiphase coexistence utilizable in novel smart materials. Among the binary colloids, niobate-clay binary nanosheet colloids are characterized by unusual photochemical functions and phase separation at a mesoscopic (∼several tens of micrometers) scale. The present study clarifies the colloidal state of the clay nanosheets in the mesostructured aqueous binary colloid of hexaniobate and fluorohectorite clay nanosheets by using small-angle neutron scattering (SANS) with the contrast variation technique. Compared to small-angle X-ray scattering (SAXS) that preferentially detects the niobate nanosheets, contrast variation SANS measurements can match out each nanosheet species to detect liquid crystalline ordering of each nanosheet species. The SANS results demonstrate the coexistence of two liquid crystalline phases induced by niobate and clay nanosheets, respectively, in the niobate-clay binary nanosheet colloids.

    DOI： 10.1039/d5sm01056j

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  • 2D Photonic Colloidal Liquid Crystals Composed of Self‐Assembled Rod‐Shaped Particles

    Riki Kato, Takahiro Mikami, Takashi Kato

    Advanced Materials   2024.9

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1002/adma.202404396

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  • Monodisperse nanosheet mesophases

    Nobuyoshi Miyamoto, Momoka Miyoshi, Riki Kato, Yuji Nakashima, Hiroyuki Iwano, Takashi Kato

    Science Advances   10 ( 23 )   2024.6

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    Publishing type：Research paper (scientific journal)   Publisher：American Association for the Advancement of Science (AAAS)  

    Self-assemblies of anisotropic colloidal particles into colloidal liquid crystals and well-defined superlattices are of great interest for hierarchical nanofabrications that are applicable for various functional materials. Inorganic nanosheets obtained by exfoliation of layered crystals have been highlighted as the intriguing colloidal units; however, the size polydispersity of the nanosheets has been preventing precise design of the assembled structures and their functions. Here, we demonstrate that the anionic titanate nanosheets with monodisperse size reversibly form very unusual superstructured mesophases through finely tunable weak attractive interactions between the nanosheets. Transmission electron microscopy, polarizing optical microscopy, small-angle x-ray scattering, and confocal laser scanning microscopy clarified the reversible formation of the mesophases (columnar nanofibers, columnar nematic liquid crystals, and columnar nanofiber bundles) as controlled by counter cations, nanosheet concentration, solvent, and temperature.

    DOI： 10.1126/sciadv.adk6452

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  • Nanostructure Control in Zinc Oxide Films and Microfibers through Bioinspired Synthesis of Liquid‐Crystalline Zinc Hydroxide Carbonate; Formation of Free‐Standing Materials in Centimeter‐Level Lengths

    Takahiro Mikami, Riki Kato, Yoshihiro Hosokawa, Nobuyoshi Miyamoto, Takashi Kato

    Small Methods   2024.4

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1002/smtd.202300353

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  • Time evolution of the inner structure of antimony phosphate nanosheet suspension developing structural colouration

    Emiko Mouri, Takashi Fukumoto, Riki Kato, Nobuyoshi Miyamoto, Teruyuki Nakato

    Soft Matter   20 ( 32 )   6353 - 6360   2024

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    Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

    Structural colouration observed in antimony phosphate nanosheet suspensions has been known for two decades, but the stability of their inner structure has not been a topic in colloidal nanosheet systems.

    DOI： 10.1039/d4sm00647j

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  • Thermotropic Colloidal Liquid‐Crystalline Hydroxyapatite Nanorod Hybrids Containing a Forklike Mesogen

    Junya Uchida, Ryuta Kiguchi, Riki Kato, Takashi Kato

    Helvetica Chimica Acta   2023.8

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1002/hlca.202300053

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  • Development of liquid-crystalline smectic nanoporous membranes for the removal of SARS-CoV-2 and waterborne viruses

    Takeshi Sakamoto, Kazuhiro Asakura, Naru Kang, Riki Kato, Miaomiao Liu, Tsuyoshi Hayashi, Hiroyuki Katayama, Takashi Kato

    Journal of Materials Chemistry A   2023

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1039/D3TA02705H

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  • Degradable and Nanosegregated Elastomers with Multiblock Sequences of Biobased Aromatic Mesogens and Biofunctional Aliphatic Oligocarbonates

    Yuya Watanabe, Riki Kato, Kazuki Fukushima, Takashi Kato

    Macromolecules   2022.12

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1021/acs.macromol.2c01747

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  • Bioinspired macromolecular templates for crystallographic orientation control of ZnO thin films through zinc hydroxide carbonate

    Takahiro Mikami, Shunichi Matsumura, Rino Ichikawa, Riki Kato, Junya Uchida, Tatsuya Nishimura, Takashi Kato

    Polymer Journal   2022.9

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    Language：English   Publishing type：Research paper (scientific journal)  

    <jats:title>Abstract</jats:title><jats:p>The biomineralization-inspired preparation of inorganic hybrid materials has attracted attention. Here, we report a new approach to the orientation control of zinc oxide (ZnO) thin-film crystals through the preparation of zinc hydroxide carbonate (ZHC) by the macromolecular templates of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(vinyl alcohol) (PVA). Using 100-nm-thick PHEMA templates, ZHC thin films with the<jats:italic>c</jats:italic>-axis oriented parallel to the substrate were obtained, while ZHC thin films prepared by 100-nm-thick PVA templates showed perpendicular orientation. After the thermal treatment of ZHC, the crystal orientations of the ZnO thin films were maintained. The effects of the thickness and annealing time for the polymer templates on the morphologies of the ZnO thin films were examined.</jats:p>

    DOI： 10.1038/s41428-022-00661-9

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  • Perovskite Nanosheet Hydrogels with Mechanochromic Structural Color

    Wenqi Yang, Shinya Yamamoto, Keiichiro Sueyoshi, Takumi Inadomi, Riki Kato, Nobuyoshi Miyamoto

    Angewandte Chemie   2021.4

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    Language：English   Publishing type：Research paper (scientific journal)  

    <jats:title>Abstract</jats:title><jats:p>Structural color colloidal sols of perovskite nanosheets were synthesized and were immobilized in a polymer hydrogel film by in situ photopolymerization, leading to a novel mechanochromic material. Visible absorption spectroscopy, polarized optical microscopy and small‐angle X‐ray scattering revealed that the nanosheets are aligned parallel to the film surface with the periodic distance of up to ca. 300 nm, giving the structural color tunable over full color range. The present structural color gel showed reversible mechanochromic response that detects weak stress of 1 kPa with the quick response time less than 1 ms as well as high mechanical toughness (compressive breaking stress of up to 3 MPa). These excellent properties are suitable for applications for mechano‐sensors and displays.</jats:p>

    DOI： 10.1002/ange.202015982

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  • Structure-regulated tough elastomers of liquid crystalline inorganic nanosheet/polyurethane nanocomposites

    Toki Morooka, Yutaka Ohsedo, Riki Kato, Nobuyoshi Miyamoto

    Materials Advances   2021

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    Language：English   Publishing type：Research paper (scientific journal)  

    <p>Liquid crystalline nanosheet/polyurethane composite elastomers with superior mechanical properties were successfully synthesized using the newly developed<italic>in situ</italic>polymerization technique.</p>

    DOI： 10.1039/d0ma00768d

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  • High Virus Removal by Self‐Organized Nanostructured 2D Liquid‐Crystalline Smectic Membranes for Water Treatment

    Daniel Kuo, Miaomiao Liu, K. R. Sunil Kumar, Kazuma Hamaguchi, Kian Ping Gan, Takeshi Sakamoto, Takafumi Ogawa, Riki Kato, Nobuyoshi Miyamoto, Hiroki Nada, Masahiro Kimura, Masahiro Henmi, Hiroyuki Katayama, Takashi Kato

    Small   2020.6

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    Language：English   Publishing type：Research paper (scientific journal)  

    <jats:title>Abstract</jats:title><jats:p>To obtain high quality of drinking water free from biocontaminants is especially important issue. A new strategy employing smectic liquid‐crystalline ionic membranes exhibiting 2D structures of layered nanochannels for water treatment is proposed for efficient virus removal and sufficient water flux. The smectic A (SmA) liquid‐crystalline membranes obtained by in situ polymerization of an ionic mesogenic monomer are examined for removal of three distinct viruses with small size: Qβ bacteriophage, MS2 bacteriophage, and Aichi virus. The semi‐bilayer structure of the SmA significantly obstructs the virus penetration with an average log reduction value of 7.3 log<jats:sub>10</jats:sub> or the equivalent of reducing 18 million viruses down to 1. Furthermore, the layered nanochannels of the SmA liquid crystal allow efficient water permeation compared to other types of liquid‐crystalline membrane consisting of nanopores.</jats:p>

    DOI： 10.1002/smll.202001721

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  • Design and phase transition behavior of siloxane-based monomeric and dimeric liquid crystals bearing cholesteryl mesogenic groups

    Kaito Katsuki, Kosuke Kaneko, Kimiyoshi Kaneko, Riki Kato, Nobuyoshi Miyamoto, Tomonori Hanasaki

    Journal of Organometallic Chemistry   2019.4

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1016/j.jorganchem.2019.02.016

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  • Liquid Crystalline Colloidal Mixture of Nanosheets and Rods with Dynamically Variable Length

    Riki Kato, Akira Kakugo, Kazuhiro Shikinaka, Yutaka Ohsedo, ARIF MD. RASHEDUL KABIR, Nobuyoshi Miyamoto

    ACS Omega   2018.11

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1021/acsomega.8b01050

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MISC

  • A20 単分散チタニアナノシートへの [Ru(bpy)3]2+錯体の導入と機能化

    岩野 広幸, 中嶌 裕二, 三好 桃佳, 加藤 利喜, 加藤 隆史, 宮元 展義

    粘土科学討論会講演要旨集   66   53 - 54   2023.9

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    Language：Japanese   Publisher：一般社団法人日本粘土学会  

    DOI： 10.11362/cssj2.66.0_53

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  • B12 種々の長鎖アルキルアンモニウムのインターカレーションによる単分散ナノシート積層型ファイバーの安定化

    中嶌 裕二, 加藤 利喜, 三好 桃佳, 加藤 隆史, 宮元 展義

    粘土科学討論会講演要旨集   65   87 - 88   2022.9

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    Language：Japanese   Publisher：一般社団法人日本粘土学会  

    DOI： 10.11362/cssj2.65.0_87

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  • Mechanochromic Inorganic Nanosheet Gel with Structural Color

    Yang Wenqi, Inadomi Takumi, Katou Riki, Miyamoto Nobuyoshi, Gong Jian Ping

    Proceedings of Japanese Liquid Crystal Society Annual meeting   2022   PF01   2022

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    Language：Japanese   Publisher：THE JAPANESE LIQUID CRYSTAL SOCIETY  

    In this research, the synthesized perovskite nanosheet colloid with structural color was immobilized into polymer hydrogel by in-situ photo-initiated polymerization to develop a novel mechanochromic material. The parallel structure of nanosheet inner the gel was confirmed by UV-Vis reflective spectrum, small angle X-ray scattering. The structural color of the hydrogel is adjustable in full-color range. The hydrogel exhibits a reversible mechanochromic property of responding to weak mechanical stimuli less than 1 kPa within 1 ms. These excellent properties can be applied to mechano sensors and displays.

    DOI： 10.11538/ekitou.2022.0_pf01

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  • B11 単分散ナノシートコロイドが形成する液晶相

    三好 桃佳, 加藤 利喜, 吉岡 大輔, 宮元 展義

    粘土科学討論会講演要旨集   63   83 - 84   2019.9

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    Language：Japanese   Publisher：一般社団法人日本粘土学会  

    DOI： 10.11362/cssj2.63.0_83

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  • A17 巨大配向ドメインを示すモンモリロナイトナノシートコロイド

    加藤 利喜, 宮元 展義

    粘土科学討論会講演要旨集   63   55 - 56   2019.9

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    Language：Japanese   Publisher：一般社団法人日本粘土学会  

    DOI： 10.11362/cssj2.63.0_55

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  • B6 非水溶媒分散型ナノシートコロイドの液晶性と粘弾性

    宮元 展義, 岩下 亮, 加藤 利喜, 山本 伸也

    粘土科学討論会講演要旨集   62   76 - 77   2018.9

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    Language：Japanese   Publisher：一般社団法人日本粘土学会  

    DOI： 10.11362/cssj2.62.0_76

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  • Liquid crystalline clay nanosheet colloids that spontaneously forms huge oriented domain

    Kato Riki, Miayamoto Nobuyoshi

    Proceedings of Japanese Liquid Crystal Society Annual meeting   2018   1B03   2018

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    Language：Japanese   Publisher：THE JAPANESE LIQUID CRYSTAL SOCIETY  

    DOI： 10.11538/ekitou.2018.0_1b03

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  • Preparation of non-aqueous nanosheets colloids with liquid crystallinity and their structure and viscoelastic properties

    Iwashita Ryo, Kato Riki, Yamamoto Shinya, Miyamoto Nobuyoshi

    Proceedings of Japanese Liquid Crystal Society Annual meeting   2017   2B09   2017

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    Language：Japanese   Publisher：THE JAPANESE LIQUID CRYSTAL SOCIETY  

    DOI： 10.11538/ekitou.2017.0_2b09

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Presentations

  • ナノ粒子が自己組織化した機能性コロイド液晶 Invited

    加藤利喜

    第35回日本MRS年次大会  2025.11.10 

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  • 水圏合成で得られた生分解性無機コロイド液晶のフォトニック機能 Invited

    加藤利喜

    第14回CSJ化学フェスタ2024  2024.10.22 

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    Presentation type：Oral presentation (invited, special)  

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Awards

  • 論文賞A

    2022.9   日本液晶学会  

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  • 優秀講演賞

    2017.9   日本化学会低次元系光機能材料研究会  

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Research Projects

  • 動的フォトニック機能を示すハイブリッドコロイド液晶の構築

    Grant number：25K01625  2025.04 - 2029.03

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    加藤 利喜, 仁科 勇太, 加藤 隆史

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    Grant amount：\18720000 （ Direct expense: \14400000 、 Indirect expense：\4320000 ）

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  • ねじれ棒状液晶性粒子の合成とコレステリック相に基づく構造色の発現

    Grant number：22K14562  2022.04 - 2024.03

    日本学術振興会  科学研究費助成事業  若手研究

    加藤 利喜

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    Grant amount：\4680000 （ Direct expense: \3600000 、 Indirect expense：\1080000 ）

    従来の無機物ベースのコロイド液晶は単純な形状の粒子からなり、有機物からなる液晶と比べて単純配向しただけの液晶であったため、機能性に乏しかった。そこで本研究では、生物が鉱物を生み出すバイオミネラリゼーションに倣うことで、構造色を示す新規コロイド液晶の開発を目的とする。具体的にはアミノ酸存在下で結晶成長を行うことによってねじれ棒状粒子を合成し、その形状によって誘起されたコレステリック相による構造色材料の開発を最終目標としている。
    2022年度では、まずバイオミネラリゼーションに倣い、アパタイトベース粒子の合成条件を検討した。その結果、非常に粒径分布の狭い液晶性棒状粒子の合成に成功した。基本的な粒子構造や液晶性の評価を行った。次にアミノ酸存在下でアパタイトベースの粒子を合成することを試みた。すると予想に反してねじれ構造ではなく、長さは850nm、直径150nm程度の紡錘状の粒子を合成することができた。その粒子の形状やサイズはアミノ酸種や濃度などの合成条件によって制御することができ、最大で長さ3μmを超える粒子も合成できた。直径に対する長さのアスペクト比が６程度であったため、比較的高い粒子濃度で液晶相を形成した。さらに、特定の条件下ではその液晶構造に基づいていると思われる構造色を示した。当初の予定であったコレステリック相からなる構造色ではなかったが、新奇構造色材料として粒子の構造、液晶性、構造色についての評価を行った。

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