Title: Flow-induced concentration fluctuations in polymer-solutions - structure property relationships
Authors: Moldenaers, Paula ×
Yanase, H
Mewis, Joannes
Fuller, Gg
Lee, Cs
Magda, Jj #
Issue Date: Jan-1993
Publisher: Dr dietrich steinkopff verlag
Series Title: Rheologica acta vol:32 issue:1 pages:1-8
Abstract: Mechanical and optical rheometric measurements are reported on solutions of polystyrene dissolved in dioctyl phthalate, a solution that can undergo an apparent phase separation upon the application of shear. Solutions prepared using three molecular weights ranging from one to four million were studied. Time-temperature superposition was observed to apply for these solutions up to and including the onset of an apparent shear thickening of the steady shear and first normal stresses. Optical measurements employing turbidity and scattering dichroism determined that concentration fluctuations were enhanced by flow and grew parallel to the vorticity axis below the critical velocity gradient for the onset of the apparent shear thickening effect. Prior to the onset of thickening, the fluctuations were observed to rearrange and orient parallel to the flow direction. Second normal stress difference measurements indicate these solutions have a negative ratio of the second to the first normal stress differences. It is interesting to point out that the ratio tends to zero in the vicinity of the shear rate range at which shear thickening occurs.
ISSN: 0035-4511
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Chemical Engineering - miscellaneous
Soft Matter, Rheology and Technology Section
× corresponding author
# (joint) last author

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