This title appears in the Scientific Report :
2019
Please use the identifier:
http://hdl.handle.net/2128/23460 in citations.
Please use the identifier: http://dx.doi.org/10.1007/s00396-019-04567-6 in citations.
Tunable viscosity modification with diluted particles: when particles decrease the viscosity of complex fluids
Tunable viscosity modification with diluted particles: when particles decrease the viscosity of complex fluids
While spherical particles are the most studied viscosity modifiers, they are well known only to increase viscosities, in particular at low concentrations of approx. 1%. Extended studies and theories on non-spherical particles in simple fluids find a more complicated behavior, but still a steady incr...
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Personal Name(s): | Gvaramia, Manuchar |
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Mangiapia, Gaetano / Pipich, Vitaliy / Appavou, Marie-Sousai / Jaksch, Sebastian / Holderer, Olaf / Rukhadze, Marina D. / Frielinghaus, Henrich (Corresponding author) | |
Contributing Institute: |
Neutronenstreuung; JCNS-1 JCNS-FRM-II; JCNS-FRM-II |
Published in: | Colloid & polymer science, 297 (2019) 11-12, S. 1507-1517 |
Imprint: |
Heidelberg
Springer
2019
|
DOI: |
10.1007/s00396-019-04567-6 |
Document Type: |
Journal Article |
Research Program: |
Jülich Centre for Neutron Research (JCNS) FRM II / MLZ Soft Matter, Health and Life Sciences |
Subject (ZB): | |
Link: |
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Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1007/s00396-019-04567-6 in citations.
While spherical particles are the most studied viscosity modifiers, they are well known only to increase viscosities, in particular at low concentrations of approx. 1%. Extended studies and theories on non-spherical particles in simple fluids find a more complicated behavior, but still a steady increase with increasing concentration. Involving platelets in combination with complex fluids – in our case a bicontinuous microemulsion – displays an even more complex scenario that we analyze experimentally and theoretically as a function of platelet diameter using small angle neutron scattering, rheology and the theory of the lubrication effect, to find the underlying concepts. The clay particles effectively form membranes in the medium that itself may have lamellar aligned domains and surfactant films in the case of the microemulsion. The two-stage structure of clay and surfactant membranes explains the findings using the theory of the lubrication effect. This confirms that layered domain structures serve for lowest viscosities. Starting from these findings and transferring the condition for low viscosities to other complex fluids, namely crude oils, even lowered viscosities with respect to the pure crude oil were observed. This strengthens our belief that also here layered domains are formed as well. This apparent contradiction of a viscosity reduction by solid particles could lead to a wider range of applications where low viscosities are desired. The same concepts of two-stage layered structures also explain the observed conditions for extremely enhanced viscosities at particle concentrations of 1% that may be interesting for the food industry. |