Abstract
This report describes characterization of molecular motions of water confined in well-defined 10 nm - 100 nm scale channels on a microchip (called extended-nano spaces) based on NMR spectroscopy results. We found that the relaxation rates of water were increased by size-confinement in the range of not only 200 - 800 nm but also 4 - 40 nm, while the rates did not depend on the space sizes of 40 - 200 nm. These results could be expressed quantitatively by a three-phase exchange model suggesting that the water motions in extended-nano spaces are controlled by the fraction of three phases, including the bulk phase (SB), the proton transfer phase (SP), and the adsorbed phase (Sa). © 2006 Society for Chemistry and Micro-Nano Systems.