Paper Number
GG40 

Session
Rheology of Gels, Glasses and Jammed Systems

Title
Structural ordering and particle dynamics in a dense silica colloid

Presentation Date and Time
October 12, 2022 (Wednesday) 11:30

Track / Room
Track 3 / Sheraton 5

Authors (Click on name to view author profile)

1. Lin, Xiao-Min (Argonne National Laboratory, Center for Nanoscale Materials)
2. He, HongRui (Argonne National Laboratory, Materials Science Division and Center for Molecular Engineer)
3. Lee, Jonghun (Argonne National Laboratory, Advanced Photon Source)
4. He, Qiming (Argonne National Laboratory, Materials Science Division and Center for Molecular Engineer)
5. Dinic, Jelena (Argonne National Laboratory, Materials Science Division and Center for Molecular Engineer)
6. Chen, Wei (Argonne National Laboratory, Materials Science Division and Center for Molecular Engineer)
7. Jiang, Zhang (Argonne National Laboratory, Advanced Photon Source)
8. Narayanan, Suresh (Argonne National Laboratory, Advanced Photon Source)

Author and Affiliation Lines (in printed abstract book)
Xiao-Min Lin¹, HongRui He², Jonghun Lee³, Qiming He², Jelena Dinic², Wei Chen², Zhang Jiang³ and Suresh Narayanan^3
1Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL 60439; ²Materials Science Division and Center for Molecular Engineer, Argonne National Laboratory, Lemont, IL 60439; ³Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439

Speaker / Presenter 
Lin, Xiao-Min

Keywords
experimental methods; colloids; glasses; jammed systems; suspensions

Text of Abstract
Externally applied shear on a dense colloid can induce structural changes as well as influence the local particle dynamics, which leads to a complex rheological response. Using in situ Rheo-SAXS-XPCS instrument, we found that within certain particle size range and volume fractions, ordering and disordering of particles can occur driven by an oscillatory shear of the system, whereas steady shear can bypass the transition all together. This transition is purely controlled by the strain amplitude, different from the normal shear thickening behavior that occurs at a much higher critical shear stress. Time dependent study under different shear strain amplitudes reveals that the strain amplitude controls the different degree of ordering. The pathway towards the local dynamic structure equilibrium can also become highly non-monotonic and is influenced by the phase of the oscillation. XPCS study after stopping the shear in the shear thickening regime, reveals heterogenous particle dynamics, which is likely caused by friction induced partially jammed network.