Journal
JOURNAL OF RHEOLOGY
Volume 53, Issue 2, Pages 357-381Publisher
SOC RHEOLOGY
DOI: 10.1122/1.3058438
Keywords
colloids; rheology; suspensions; viscosity
Categories
Funding
- National Science Foundation [CBET-0238689, CBET-0730292]
- Procter and Gamble Company
Ask authors/readers for more resources
We measure the microviscosity of a colloidal suspension using active, oscillatory laser tweezer microrheology. Our results are compared to a new theoretical model that explicitly accounts for different bath and probe particle sizes and the three independent contributions to the stress: direct interactions (collisions) between the probe and suspension particles; indirect interactions between suspension particles; and the Einstein contribution of the suspension particles. Notably, direct and indirect interactions give rise to two characteristic and highly separated dimensionless frequencies or Peclet numbers as the probe diameter becomes large relative to the average suspension particle diameter, but are identical in the limit that the diameters are equal. The experimental microviscosities are consistent with indirect interactions dominating the direct bath-probe collisions in the large probe limit. This enables a reinterpretation of previous drag microrheology experiments in the large probe limit, further confirming the promise that microrheology can, by actively driving the probe particle, be adapted to measure the nonlinear rheology of complex fluids.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available