Paper Number
PO78 

Session
Poster Session

Title
Magnetic microrollers maneuvering in a colloidal suspension

Presentation Date and Time
October 12, 2022 (Wednesday) 6:30

Track / Room
Poster Session / Riverwalk A

Authors (Click on name to view author profile)

1. Chen, Shih-Yuan (Northwerstern University, Physics)
2. Driscoll, Michelle M. (Northwestern University, Physics)

Author and Affiliation Lines (in printed abstract book)
Shih-Yuan Chen¹ and Michelle M. Driscoll^2
1Physics, Northwerstern University, Chicago, IL 60660; ²Physics, Northwestern University, Evanston, IL 60208

Speaker / Presenter 
Chen, Shih-Yuan

Keywords
experimental methods; colloids; suspensions

Text of Abstract
Micro swimmers in a fluid can either self-propel or be driven by external forces. The interactions between micro swimmers and their surroundings lead to a wide range of phenomena: self-assembly, phase separation, transportation of cargo, etc. Likewise, studying such interactions helps us to probe local rheology and material parameters such as the effective viscosity of a colloidal solution or the viscoelasticity of a non-Newtonian fluid. In this presentation, I will demonstrate how magnetically driven microrollers maneuver in structured environments. When the rollers are spun by an external magnetic field, they pump fluid around themselves, driving them to move in the desired direction. This also generates strong flows that can reconfigure the nearby environment. I will show how the microrollers restructure passive colloids to form a new, steady configuration, and argue that the balance between Brownian motion and the flow velocity determines the size of the structure, which is an order of magnitude larger than the roller.