2017/10/11 by Lilian C. Hsiao, Safa Jamali, Emmanouil Glynos +3 · 1 citation
Engineering · Chemical Engineering · Materials Science · #Granular flow and fluidized beds #Rheology and Fluid Dynamics Studies #Material Dynamics and Properties
paper · pdf · doi:10.1103/physrevlett.119.158001
openalex publication_date 2017/10/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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.