Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

A rheological signature of frictional interactions in shear thickening suspensions



John R. Royer, Daniel L. Blair, Steven D Hudson


Understanding shear thickening presents a significant challenge in colloidal physics. As the applied shear pushes particles into close contact, the macroscopic rheology is increasingly controlled by the microscopic details of short ranged particle interactions. We elucidate the relative contributions from hydrodynamic lubrication and frictional contact forces to colloidal shear thickening by measuring both the viscosity $\eta$ and first normal stress difference $N_1$ in suspensions of silica spheres over a wide range of volume fractions. The first normal stress difference reveals a transition not apparent in the viscosity alone, from $N_1 0$ at larger values of $\phi$. While the $N_1 0$ behavior (dilation) is instead a characteristic of frictional `granular' suspensions. Fitting our viscosity profiles $\eta(\sigma, \phi)$ to a model for friction-driven shear thickening, we capture the shear thickening for $\phi \geq 0.52$ but must adjust the adjust the maximum fraction of frictional contacts to fit at lower volume fractions. Our results bring together two contrasting theories for shear thickening; they show that friction drives shear thickening in concentrated colloidal suspensions, but also highlight the need to include hydrodynamic effects to fully describe the rheology at moderate concentrations.
Physical Review Letters


shear thickening, colloids, fluid suspensions, rheology, friction between colloidal particles


Royer, J. , Blair, D. and , S. (2016), A rheological signature of frictional interactions in shear thickening suspensions, Physical Review Letters, [online], (Accessed May 28, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created May 5, 2016, Updated November 10, 2018