Elucidation of surface effect on molecular dynamics in confined space

2021 Fiscal Year Final Research Report

• 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
• Keywords: 中性子準弾性散乱 / 制限空間 / 水

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.

Free Research Field

中性子準弾性散乱、制限空間中のダイナミクス

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。