Rheological State Diagrams for Rough Colloids in Shear Flow
Name
PhysRevLett.119.158001.pdf
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Author(s)
Hsiao, Lilian C.
Glynos, Emmanouil
Green, Peter F.
Larson, Ronald G.
Solomon, Michael J.
Jamali, Seyedsafa
Date Issued
October 2017
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Hsiao, Lilian C. et al. "Rheological State Diagrams for Rough Colloids in Shear Flow." Physical Review Letters 119, 15 (October 2017): 158001 © 2017 American Physical Society
Version
Final published version
Abstract
To assess the role of particle roughness in the rheological phenomena of concentrated colloidal suspensions, we develop model colloids with varying surface roughness length scales up to 10% of the particle radius. Increasing surface roughness shifts the onset of both shear thickening and dilatancy towards lower volume fractions and critical stresses. Experimental data are supported by computer simulations of spherical colloids with adjustable friction coefficients, demonstrating that a reduction in the onset stress of thickening and a sign change in the first normal stresses occur when friction competes with lubrication. In the quasi-Newtonian flow regime, roughness increases the effective packing fraction of colloids. As the shear stress increases and suspensions of rough colloids approach jamming, the first normal stresses switch signs and the critical force required to generate contacts is drastically reduced. This is likely a signature of the lubrication films giving way to roughness-induced tangential interactions that bring about load-bearing contacts in the compression axis of flow.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.119.158001
