Journal Article

PreJuSER-27238

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Flow dichroism in critical colloidal fluids

Lenstra, T.FZJ* ; Dhont, J. K. G.FZJ*

2001
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/1606

Abstract: Due to long-range correlations and slow dynamics of concentration fluctuations in the vicinity of the gas-liquid critical point, shear flow is very effective in distorting the microstructure of near-critical fluids. The anisotropic nature of the shear-field renders the microstructure highly anisotropic, leading to dichroism. Experiments on the dichroic behavior can thus be used to test theoretical predictions on microstructural order under shear flow conditions. We performed both static and dynamic dichroism and turbidity measurements on a colloid-polymer mixture, existing of silica spheres (radius 51 nm) and polydimethylsiloxane polymer (molar weight 204 kg/mol). Sufficiently far away from the critical point, in the mean-field region, the experimental data are in good agreement with theory. Very close to the critical point, beyond mean field, for which no theory exists yet, an unexpected decrease of dichroism on approach of the critical point is observed. Moreover, we do not observe critical slowing down of shear-induced dichroism, right up to the critical point, in contrast to the turbidity.

Keyword(s): J

Note: Record converted from VDB: 12.11.2012

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Contributing Institute(s):

1. Weiche Materie (IFF-WM)

Research Program(s):

1. Polymere, Membranen und komplexe Flüssigkeiten (23.30.0)

Appears in the scientific report 2001
Notes: This version is available at the following Publisher URL: http://pre.aps.org

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