Diffusion Dynamics of Water and Ethanol in Graphene Oxide.

Autor:	Acharya GR; Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201, United States., Tyagi M; NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, United States.; Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States., Mamontov E; Neutron Scattering Division, Oak Ridge National Laboratory, P.O. Box 2008 MS6473, Oak Ridge, Tennessee 37831, United States., Hoffmann PM; Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201, United States.; Department of Physical Sciences, Embry-Riddle Aeronautical University, Daytona Beach, Florida 32114, United States.
Jazyk:	angličtina
Zdroj:	The journal of physical chemistry. B [J Phys Chem B] 2023 Aug 24; Vol. 127 (33), pp. 7384-7393. Date of Electronic Publication: 2023 Aug 09.
DOI:	10.1021/acs.jpcb.2c08960
Abstrakt:	We utilized the momentum transfer ( Q )-dependence of quasi-elastic neutron scattering (QENS) to measure the dynamics of water and ethanol confined in graphene oxide (GO) powder or membranes at different temperatures and in different orientations. We found reduced diffusivities (up to 30% in the case of water) and a depression of dynamic transition temperatures. While water showed near Arrhenius behavior with an almost bulk-like activation barrier in a temperature range of 280-310 K, the diffusivity of ethanol showed little temperature dependence. For both water and ethanol, we found evidence for immobile and mobile fractions of the confined liquid. The mobile fraction exhibited jump diffusion, with a jump length consistent with the expected average spacing of hydroxide groups in the GO surfaces. From anisotropy measurements, we found weak anisotropy in the diffusivity of the mobile species and in the fraction and geometry of immobile species.
Databáze:	MEDLINE
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