Journal Article

PreJuSER-22197

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Structure and dynamics of water in nonionic reverse micelles: A combined time-resolved infrared and small angle x-ray scattering study

van der Loop, T. H. ; Panman, M. R. ; Lotze, S. ; Zhang, J.FZJ* ; Vad, T. ; Bakker, H. J. ; Sager, W. F. C.FZJ* ; Woutersen, S.

2012
American Institute of Physics Melville, NY

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Please use a persistent id in citations: http://hdl.handle.net/2128/7517  doi:10.1063/1.4736562

Abstract: We study the structure and reorientation dynamics of nanometer-sized water droplets inside nonionic reverse micelles (water/Igepal-CO-520/cyclohexane) with time-resolved mid-infrared pump-probe spectroscopy and small angle x-ray scattering. In the time-resolved experiments, we probe the vibrational and orientational dynamics of the O-D bonds of dilute HDO:H(2)O mixtures in Igepal reverse micelles as a function of temperature and micelle size. We find that even small micelles contain a large fraction of water that reorients at the same rate as water in the bulk, which indicates that the polyethylene oxide chains of the surfactant do not penetrate into the water volume. We also observe that the confinement affects the reorientation dynamics of only the first hydration layer. From the temperature dependent surface-water dynamics, we estimate an activation enthalpy for reorientation of 45 ± 9 kJ mol(-1) (11 ± 2 kcal mol(-1)), which is close to the activation energy of the reorientation of water molecules in ice.

Keyword(s): J

Note: The authors would like to thank Stichting voor Fundamenteel Onderzoek der Materie (FOM) for financial support and Dr. P. Konarev (EMBL-Hamburg) for assistance in performing the SAXS experiments.

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Contributing Institute(s):

1. Weiche Materie (ICS-3)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)

Appears in the scientific report 2012

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Database coverage:
; ; ; Allianz-Lizenz / DFG ; Current Contents - Social and Behavioral Sciences ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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