Henry C. Fu, James N. Wilking

Subject Area

Bioengineering and Biomedical Engineering, Mechanical Engineering, Physics


Microscale propulsion impacts a diverse array of fields, with simplistic microrobots allowing for novel innovations in microscale surgery and drug delivery. Propulsion at the microscale is constrained by physics, with time-reversal and geometric symmetries limiting available propulsion mechanisms. However, certain fluid environments and surface coatings allow for the propulsion of microparticles through externally applied magnetic fields. Presented here is a detailed analysis of microparticles propelling using spontaneous symmetry breaking, flagella surface coatings, and multi-modal actuation mechanisms. Spontaneous symmetry breaking in nonlinearly viscoelastic fluids is presented for the first time in literature, with two equal and opposite propulsion states existing along a microparticles rotation axis. Flagellated microparticles suspended in Newtonian fluids are demonstrated to have diverse behavior in response to rotating magnetic field frequency and direction. Finally, catalytic Janus particles were developed which could exhibit catalytic propulsion and swimming propulsion interchangeably. The continued exploration of these propulsion mechanisms will be used to further circumvent restrictions on propulsion, helping to revise notions of microrobotic design and control, drug delivery, microscale pumping, and locomotion of microorganisms.

Degree Date

Winter 12-19-2020

Document Type


Degree Name



Mechanical Engineering


Dr. Min Jun Kim

Second Advisor

Dr. Ali Beskok

Third Advisor

Dr. Pia Vogel

Fourth Advisor

Dr. Edmond Richer

Fifth Advisor

David Willis

Number of Pages




Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.