Paper Number
SC14 James Swan Memorial Symposium
Session
Suspensions and Colloids
Title
Modeling rough colloidal gels using Stokesian dynamics simulations
Presentation Date and Time
October 10, 2022 (Monday) 4:25
Track / Room
Track 1 / Sheraton 4
Authors
- Majji, Madhu V (Massachusetts Institute of Technology, Department of Chemical Engineering)
- Swan, James W. (Massachusetts Institute of Technology, Chemical Engineering)
Author and Affiliation Lines
Madhu V Majji and James W. Swan
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
Speaker / Presenter
Majji, Madhu V
Keywords
computational methods; colloids; gels; suspensions
Text of Abstract
Colloidal gels made of rough particles such as carbon black, fumed silica, or engineered raspberry-like particles display significantly different material properties compared to the gels made of smooth colloids. A significant contribution to this difference arises from the fact that rough colloids in shear flow interact differently at close separations compared to the smooth colloids and hence produce different microstructures. Understanding how the surface roughness of colloids affects the microstructure and the macroscopic material properties of resultant gels is important given their applications in suspension electrolytes for flow batteries, paints, and consumer care products. We developed a thermodynamically consistent, pair-wise hydrodynamic model to simulate the near-field hydrodynamic interactions between rough particles under shear flow. We integrated this model with Stokesian dynamics and simulated the microstructure of rough colloidal gels subjected to linear shear flow. In addition to the hydrodynamic interactions, the colloidal interactions include a short-range depletion attraction and a long-range electrostatic repulsion. In this talk, we will discuss in detail the effect of varying degrees of colloid roughness on the microstructure and the rheology of the resultant gel for different ratios of the applied shear rate and the depletion strength between colloids at contact (Mason number).