Recent Research Topics
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Hydration water dynamics at biocompatible polymers
The feature to prevent blood clotting is known as "biocompatibility", and essentially important for a coating materials of medical devices. The origin of the biocompatibility is considered to be related with the feature of hydration water, however, the details have not been understood. We have done Quasi-Elastic Neutron Scattering (QENS) experiments to investigate the dynamical properties of hydration water near polymer chains of PEO (polyethylene oxide), and confirmed an existence of a significant amount of slow mode water.
Research Features Manuscript Video Abstract
Kikuchi et al., J. Chem. Phys. (2024).
Tominaga et al., J. Phys. Chem. B (2022).
Fujii et al., Front. Chem. (2021). -
Observation of aggregation of hydrophobic solute in water-THF mixed solvent
The aggregation behavior of hydrophobic fluorescent molecule in water-tetrahydrofuran (THF) mixed solvent was observed. Water and THF molecules form varieties of micro-mesoscopic scale structures, where hydrophobic molecules are distributed to form aggregation. The aggregation state of the solute and the size of the aggregate changed upon changing the mixing ratio of water and THF, which significantly affects the fluorescence properties of the solution.
Tsuji et al., J. Phys. Chem. Lett. (2023). -
The origin of the onion formation of surfactant bilayers under shear
The aqueous solution of non-ionic surfactant is known to form bilayers and the onion morphology is induced by applying shear. We investiged this transition by SANS and Neutron Spin Echo (NSE) spectroscopy, and verified the role of the inter-membrane interactions.
Kawabata et al., J. Chem. Phys. (2017). -
Shear-induced ordering of colloidal solution of hydroxyapatite
Stimuli-responsible hydroxyapatite-based colloidal liquid crystalline nanorods were examined using in situ small-angle neutron scattering (SANS) and rheological measurements under shear. The experimental results unraveled the effects of the shear force to form the hierarchial morphologies of nano-rods and their transitions.
Kajiyama et al., Nanoscale (2020). -
The existence of three types of hydration water near lipid membranes
Lipid molecules are main components of biological membranes and their physical properties intensively. QENS experiments verified the existence of three types of hydration water as free water, loosely bound water, and tightly bound water.
Yamada et al, J. Phys. Chem. B, (2017).
Seto and Yamada, Appl. Phys. Lett. (2020).
Rahman et al., Struct. Dyn. (2023).
