Paper Number
AD3
Session
Rheology of Active Matter and Directed Systems
Title
Chaotic rheology of autophoretic colloids
Presentation Date and Time
October 12, 2022 (Wednesday) 2:10
Track / Room
Track 4 / Michigan AB
Authors
- Kailasham, R. (Carnegie Mellon University, Department of Chemical Engineering)
- Khair, Aditya (Carnegie Mellon University, Department of Chemical Engineering)
Author and Affiliation Lines
R. Kailasham and Aditya Khair
Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
Speaker / Presenter
Kailasham, R.
Keywords
computational methods; active matter; colloids; suspensions
Text of Abstract
The spontaneous self-propulsion of chemically active “autophoretic” particles is governed by the magnitude of the intrinsic Peclet number, i.e., the ratio of the emission rate of the solute to its diffusion rate. In this talk, we numerically solve for the concentration and flow fields around an autophoretic two-dimensional disk suspended in a Newtonian solvent and subjected to an ambient shear flow. At sufficiently small Peclet number, the external flow field symmetrizes the concentration field around the particle, resulting in zero phoretic velocity. The components of the stresslet, however, are found to be time dependent, and hence is the rheology of a dilute suspension of such disks. At large enough values of the Peclet number, a chaotic time series for the phoretic velocity and the stresslet are observed. The dynamics of the autophoretic disk is further analyzed in terms of its mean square displacement and is found to differ significantly from that of a passive Brownian particle in shear flow. The interplay between the shear rate and chemical activity in determining the motion of the autophoretic particle is explored, and protocols for inducing/quenching the chaotic dynamics presented.