Paper Number
SC53 

Session
Suspensions and Colloids

Title
Microscopic dynamics in charged colloidal suspensions with rheological hysteresis

Presentation Date and Time
October 12, 2022 (Wednesday) 5:25

Track / Room
Track 1 / Sheraton 4

Authors (Click on name to view author profile)

  1. He, HongRui (Argonne National Laboratory, Materials Science Division and Center for Molecular Engineer)
  2. Fang, Yan (University of Chicago, Pritzker School of Molecular Engineering)
  3. Lin, Xiao-Min (Argonne National Laboratory, Center for Nanoscale Materials)
  4. Jiang, Zhang (Argonne National Laboratory, Advanced Photon Source)
  5. Tirrell, Matthew (University of Chicago, Pritzker School of Molecular Engineering)
  6. Narayanan, Suresh (Argonne National Laboratory, Advanced Photon Source)
  7. Chen, Wei (Argonne National Laboratory, Materials Science Division and Center for Molecular Engineer)

Author and Affiliation Lines (in printed abstract book)
HongRui He1, Yan Fang2, Xiao-Min Lin3, Zhang Jiang4, Matthew Tirrell2, Suresh Narayanan4 and Wei Chen1
1Materials Science Division and Center for Molecular Engineer, Argonne National Laboratory, Lemont, IL 60439; 2Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637; 3Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL 60439; 4Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439

Speaker / Presenter 
He, HongRui

Keywords
experimental methods; colloids; spectroscopy; suspensions

Text of Abstract
Rheological hysteresis is defined as a time lag between drive and response and is attributed to time dependent microstructural changes taking place in the system. This property is often observed in concentrated colloidal suspensions since interaction among particles constitute space-filling network structures. However, due to the limitations of time and length scales in previous experimental techniques, the contributions from interparticle interactions are not well understood. In this work, we applied Rheo-XPCS, an in-situ measurement of rheology and X-ray photon correlation spectroscopy (XPCS), to investigate the evolution of dynamics of charged colloids during the recovery from applied high shear. While changes in the scattering profile is negligible during the recovery period, we observe transition from homodyne to heterodyne form of time correlation functions as shear bands build up in the system. Comparing trials of varying duration of high shear before recovery, the evolution of nanoscale dynamics and bulk rheological response are history dependent, indicating a strong correlation between the microscopic and macroscopic behaviors. This observation is a new perspective on how interaction potential of individual particles induces hysteresis properties through their local dynamics. The experimental approaches developed in this study is extended to study and interpret the rheological hysteresis behavior in the system with more complex interactions such as in the presence of salt.