Radio-frequency-range proton dynamics of the water network in nanopores

2014 Fiscal Year Final Research Report

• Project/Area Number: 24340071
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Tohoku University
• Principal Investigator: MATSUI Hiroshi 東北大学, 理学(系)研究科(研究院), 准教授 (30275292)
• Co-Investigator(Kenkyū-buntansha): TADOKORO Makoto 東京理科大学, 理学部, 教授 (60249951)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 水分子 / ナノ空孔 / プロトン伝導 / インピーダンス / プローバー / 多孔体 / 水和 / 誘電緩和

Outline of Final Research Achievements

We developed novel prober system in combination with LCR meter and impedance analyzer. Employing extremely small single crystal, complex impedance is available to measure at 20 Hz～3 GHz. By considering an appropriate equivalent circuit, we have clarified the dynamics of the water network in molecular porous crystal Ni(cyclam), and the erythritol-intercalated water network. The dielectric constant in wide range of frequency (700 Hz‐16.3 GHz) indicates the dielectric dispersion due to configurational change of electric dipole concerning strongly hydrated water molecules in the primary and secondary hydration shells. The relaxation time is three orders of magnitude smaller than one in free water. The erythritol-intercalated water network shows large dielectric constant and isotope effect, which reveal a local proton transfer generated near the erythritol molecule. We have successfully opened the way for the study of individual biological molecules by utilizing hydrophilic nanospaces.

Free Research Field

固体物理