Elucidation of surface effect on molecular dynamics in confined space

• Project/Area Number: 18K11932
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 80040:Quantum beam science-related
• Research Institution: 一般財団法人総合科学研究機構(総合科学研究センター(総合科学研究室)及び中性子科学センター(研究開発
• Principal Investigator: Yamada Takeshi 一般財団法人総合科学研究機構(総合科学研究センター(総合科学研究室)及び中性子科学センター(研究開発, 中性子科学センター, 副主任研究員 (80512318)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2018: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
• Keywords: 中性子準弾性散乱 / 制限空間 / 水 / 触媒層 / 界面 / QENS / 分子動力学シュミレーション / 分子ダイナミクス / 中性子

Outline of Final Research Achievements

The structure and dynamics of water in nanometer-scale space are influenced by the space size and its interaction with interfaces. However, the size effect and the interaction with the interface have not been well understood separately. Therefore, in this study, we investigate the effect of the interface state on water dynamics by quasi-elastic neutron scattering for (i) water dynamics I mesoporous silica having same diameter and different hydrophobicity and (ii) effect of cations on the water between phospholipid bilayers.
The results revealed that the thickness of the hydration layer where the water strongly bound to the pore surface is expected to change due to the interfacial properties, while in other spaces two types of water exist: (1) weakly bound water that is about one order of magnitude slower than the bulk water and (2) free water similar to the bulk water.

Academic Significance and Societal Importance of the Research Achievements

本研究では、界面との相互作用は界面と強く結合した水の層の厚みとして大きく現れ、残った空間ではバルク水と同程度の拡散係数を示す水、バルク水よりも一桁程度小さい拡散係数を示す水、という2種類の水が存在することを明らかにした。得られた知見は、タンパク質の構造変化、生体材料の生体適合性、セメントの硬化反応など幅広い分野で、水が果たす役割の理解に繋がると期待される。

Research Products

• [Journal Article] Dynamics of Water in a Catalyst Layer of a Fuel Cell by Quasielastic Neutron Scattering (2021)
  • Author(s): Ito Kanae、Yamada Takeshi、Shinohara Akihiro、Takata Shin-ichi、Kawakita Yukinobu
  • Journal Title: The Journal of Physical Chemistry C Volume: 125 Issue: 39 Pages: 21645-21652
  • DOI: 10.1021/acs.jpcc.1c06014
  • Peer Reviewed
• [Journal Article] Quasi-elastic neutron scattering study of the effects of metal cations on the hydration water between phospholipid bilayers (2020)
  • Author(s): Seto H.、Yamada T.
  • Journal Title: Applied Physics Letters Volume: 116 Issue: 13 Pages: 133701-133701
  • DOI: 10.1063/1.5144012
  • Peer Reviewed
• [Journal Article] Quasi-Elastic Neutron Scattering Studies on Hydration Water in Phospholipid Membranes (2020)
  • Author(s): Yamada Takeshi、Seto Hideki
  • Journal Title: Frontiers in Chemistry Volume: 8 Pages: 8-8
  • DOI: 10.3389/fchem.2020.00008
  • Peer Reviewed / Open Access
• [Presentation] ン脂質二分子膜中の水のダイナミクスへの塩添加効果及び ダイナミクス解析装置DNAの試料環境 (2022)
  • Author(s): 山田武
  • Organizer: 液体・非晶質研究会
  • Invited
• [Presentation] リン脂質二分子膜中の水のダイナミクスへの塩添加効果 (2021)
  • Author(s): 山田 武、瀬戸秀紀
  • Organizer: 2020年度量子ビームサイエンスフェスタ
  • Invited
• [Presentation] リン脂質二分子膜中の水のダイナミクスへの塩添加効果 (2019)
  • Author(s): 山田 武、瀬戸秀紀
  • Organizer: 第55回熱測定討論会
• [Presentation] Commissioning for QENS experiments at pressures of up to 200MPa (2019)
  • Author(s): T. Yamada, H. Arima, T. Hattori
  • Organizer: the 3rd J-PARC symposium (J-PARC2019)
• [Presentation] In situ Quasi Elastic Neutron Scattering of Nafion Membrane with Water Vapor Pressure Control System (2019)
  • Author(s): Takeshi YAMADA, Taiki TOMINAGA
  • Organizer: the 3rd J-PARC symposium (J-PARC2019)
• [Presentation] In-situ Quasi Elastic Neutron Scattering of Nafion Membrane (2018)
  • Author(s): Takeshi YAMADA, Taiki TOMINAGA
  • Organizer: QENS/WINS2018
  • Int'l Joint Research