Nano-viscosity of supercooled liquid measured by fluorescence correlation spectroscopy: pressure and temperature dependence and the density scaling

Meier, G.; Gapinski, J.; Banachowicz, E.; Ratajcczyk, M.; Hirtz, Kurt; Lettinga, M. P.; Patkowski, A.

doi:10.1063/1.5011196

Journal Article

FZJ-2018-01361

Nano-viscosity of supercooled liquid measured by fluorescence correlation spectroscopy: pressure and temperature dependence and the density scaling

Meier, G. (Corresponding author)FZJ* ; Gapinski, J. ; Ratajcczyk, M. ; Lettinga, M. P.FZJ* ; Hirtz, K. ; Banachowicz, E. ; Patkowski, A.

2018
American Institute of Physics Melville, NY

The journal of chemical physics 148, 094201 (2018) [10.1063/1.5011196]

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Please use a persistent id in citations: http://hdl.handle.net/2128/17698 doi:10.1063/1.5011196

Abstract: The Stokes-Einstein relation allows us to calculate apparent viscosity experienced by tracers in complex media on the basis of measured self-diffusion coefficients. Such defined nano-viscosity values can be obtained through single particle techniques, like fluorescence correlation spectroscopy (FCS) and particle tracking (PT). In order to perform such measurements, as functions of pressure and temperature, a new sample cell was designed and is described in this work. We show that this cell in combination with a long working distance objective of the confocal microscope can be used for successful FCS, PT, and confocal imaging experiments in broad pressure (0.1-100 MPa) and temperature ranges. The temperature and pressure dependent nano-viscosity of a van der Waals liquid obtained from the translational diffusion coefficient measured in this cell by means of FCS obeys the same scaling as the rotational relaxation and macro-viscosity of the system.

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