Paper Number
SC17 

Session
Suspensions, Colloids, and Granular Materials

Title
One-step, in-situ jamming point measurements by immobilization cell rheometry

Presentation Date and Time
October 22, 2019 (Tuesday) 10:40

Track / Room
Track 2 / Room 304

Authors (Click on name to view author profile)

  1. Luo, Yimin (University of Delaware, Chemical and Biomolecular Engineering)
  2. Lee, Yu-Fan (University of Delaware, Chemical and Biomolecular Engineering)
  3. Brown, Scott C. (The Chemours Company)
  4. Dennis, Kimberly A. (University of Delaware, Chemical and Biomolecular Engineering)
  5. Furst, Eric M. (University of Delaware, Chemical and Biomolecular Engineering)
  6. Wagner, Norman J. (University of Delaware, Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Yimin Luo1, Yu-Fan Lee1, Scott C. Brown2, Kimberly A. Dennis1, Eric M. Furst1, and Norman J. Wagner1
1Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716; 2The Chemours Company, Wilmington, DE 19805

Speaker / Presenter 
Luo, Yimin

Text of Abstract
Particle jamming is a challenge in handling highly concentrated slurries in a wide variety of industries, whereupon the suspension discontinuously shear thickens and dilates, often with deleterious consequences. Such systems are shear sensitive wherein a significant increase in viscosity occurs within a few percent of change in volume fraction. Thus, identifying the jamming point is critical for properties pertaining to plant operation and cost reduction. Within the colloidal rheology community, factors contributing to discontinuous shear thickening and jamming are actively under investigation. Many studies point to surface contact friction. Consequently, there is an increasing interest in relating particle properties, such as friction coefficient to the onset of jamming. Conventional rheometry identifies the jamming point by mapping out the flow curves of a few different concentrations and extrapolating to where the viscosity diverges, but risks altering the sample during consolidation and subsequent redispersion. Furthermore, the time required to measure a sufficient number of concentrations, and the accuracy of flow curves, especially when dilatant, ultimately limits the accuracy of the fit and the number of suspensions investigated. We present an alternative approach to the experimental determination of the jamming point. The procedure monitors the shear stress under constant shear as the sample is dewatered using immobilization cell rheometry. While this setup has long been used in paper industry for qualitative characterization of the water content of the pulp, here we demonstrate that it can also robustly determine the jamming point by comparing to the studies using conventional rheometry for a wide variety of systems. It is extended to study the behavior of mixtures of systems, system aging, and pH effect, a sample parameter space too vast to be screened by conventional rheometry. In addition, the method facilitates rapid determination of critical suspension properties at the point of manufacture.