Observation of a dynamic crossover in water confined in double-wall carbon nanotubes
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
- Intense Pulsed Neutron Source Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
- MER Corporation, Tucson, Arizona 85706 (United States)
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899-8562 (United States) and Department of Material Science and Engineering, University of Maryland, College Park, Maryland 20742 (United States)
High-resolution quasielastic neutron scattering spectroscopy was used to measure H{sub 2}O hydrated double-wall carbon nanotubes (DWNT). The measurements were made at a series of temperatures from 250 K down to 150 K. The relaxing-cage model was used to analyze the quasielastic spectra. We observed clear evidence of a fragile-to-strong dynamic crossover (FSC) at T{sub L}=190 K in the confined water. We further show that the mean-square atomic displacement of the hydrogen atoms in water exhibits a sharp change in slope at approximately the same temperature 190 K. Comparing the result with that obtained from the confined water in hydrophilic porous silica material MCM-41, we demonstrate experimentally that water confined in a hydrophobic substrate exhibits a lower dynamic crossover temperature by {delta}T{sub L}{approx_equal}35 K.
- OSTI ID:
- 21076229
- Journal Information:
- Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Vol. 76, Issue 2; Other Information: DOI: 10.1103/PhysRevE.76.021505; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-651X
- Country of Publication:
- United States
- Language:
- English
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