Microfluidic Rheology of Soft Colloids above and below Jamming

Kerstin Nordstrom(University of Pennsylvania), Emilie Verneuil(University of Pennsylvania), Paulo E. Arratia(University of Pennsylvania), Anindita Basu(University of Pennsylvania), Zexin Zhang(University of Pennsylvania), Arjun G. Yodh(University of Pennsylvania), J. P. Gollub(University of Pennsylvania), D. J. Durian(University of Pennsylvania)
Physical Review Letters
October 21, 2010
Cited by 191Open Access
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Abstract

The rheology near jamming of a suspension of soft colloidal spheres is studied using a custom microfluidic rheometer that provides the stress versus strain rate over many decades. We find non-Newtonian behavior below the jamming concentration and yield-stress behavior above it. The data may be collapsed onto two branches with critical scaling exponents that agree with expectations based on Hertzian contacts and viscous drag. These results support the conclusion that jamming is similar to a critical phase transition, but with interaction-dependent exponents.


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