title: Dynamics of Water Associated with Lithium Ions Distributed in Polyethylene Oxide.
abstract: The dynamics of water in polyethylene oxide (PEO)/LiCl solution has been studied with quasielastic neutron scattering experiments and molecular dynamics (MD) simulations. Two different time scales of water diffusion representing interfacial water and bulk water dynamics have been identified. The measured diffusion coefficient of interfacial water remained 5-10 times smaller than that of bulk water, but both were slowed by approximately 50% in the presence of Li(+). Detailed analysis of MD trajectories suggests that Li(+) is favorably found at the surface of the hydration layer, and the probability to find the caged Li(+) configuration formed by the PEO is lower than for the noncaged Li(+)-PEO configuration. In both configurations, however, the slowing down of water molecules is driven by reorienting water molecules and creating water-Li(+) hydration complexes. Performing the MD simulation with different ions (Na(+) and K(+)) revealed that smaller ionic radius of the ions is a key factor in disrupting the formation of PEO cages by allowing spaces for water molecules to come in between the ion and PEO.
authors.affiliation: Biology and Soft-Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.|Forschungszentrum Jülich, Jülich Center for Neutron Science, Outstation at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Forschungszentrum Jülich, Jülich Center for Neutron Science, Outstation at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Ohl
authors.affiliation: Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Souleymane O
authors.initials: SO
authors.lastname: Diallo
authors.affiliation: Forschungszentrum Jülich, Jülich Center for Neutron Science, Outstation at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.|Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Niina H
authors.initials: NH
authors.lastname: Jalarvo
authors.affiliation: Center For Nanophase Materials Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Kunlun
authors.initials: K
authors.lastname: Hong
authors.affiliation: Biology and Soft-Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Youngkyu
authors.initials: Y
authors.lastname: Han
authors.affiliation: Biology and Soft-Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Smith
authors.affiliation: Biology and Soft-Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Changwoo
authors.initials: C
authors.lastname: Do
mesh_terms: D002414:Cations, Monovalent / Q000737:chemistry; D018020:Lithium Compounds / Q000737:chemistry*; D008956:Models, Chemical; D011092:Polyethylene Glycols / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D002414:Cations, Monovalent; D018020:Lithium Compounds; D014867:Water; D011092:Polyethylene Glycols