Paper Number
SC7 

Session
Suspensions and Colloids

Title
Relationships among structure, memory, and flow in sheared in dense colloidal systems

Presentation Date and Time
October 10, 2022 (Monday) 1:30

Track / Room
Track 1 / Sheraton 4

Authors (Click on name to view author profile)

1. Arratia, Paulo E. (University of Pennsylvania, Mechanical Engineering & Applied Mechanics)
2. Galloway, Kevin L. (University of Pennsylvania)
3. Jerolmack, Doug J. (University of Pennsylvania)

Author and Affiliation Lines (in printed abstract book)
Paulo E. Arratia, Kevin L. Galloway and Doug J. Jerolmack
Mechanical Engineering & Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104

Speaker / Presenter 
Arratia, Paulo E.

Keywords
colloids; glasses; jammed systems; suspensions

Text of Abstract
How soft materials yield is a question of fundamental interest to material engineers and rheologists alike. Often, we model complex fluids from observations of the bulk response alone. However, it may be possible to predict material response by understanding the constituent particle interactions and their arrangements. This possibility is investigated here in (i) experiments with a custom built Interfacial Stress Rheometer and densely packed monolayers of repulsive particles and (ii) simulations of granular and atomic scale systems. The bulk rheology (G’, G’’) in experiments is measured while simultaneously tracking the positions of up to 50,000 particles. We quantify particle microstructure using the concept of excess entropy, which characterizes the degree of caging in the sample. Results reveal a direct relation between excess entropy and energy dissipation, that is insensitive to the nature of interactions among particles. We use this relation to build a physically-informed model that connects rheology to microstructure. Our findings suggest a framework for tailoring the rheological response of disordered materials by tuning microstructural properties.