Faculty Sponsor
Hangjie Ji
Final Abstract for URS Program
Eutectic Gallium-Indium (EGaIn) is a room-temperature liquid metal alloy that dramatically changes its surface tension and dynamics under an applied electric field. EGaIn has been used heavily in soft electronics engineering due to its high conductivity, malleability, and safety. However, the absence of mathematical modeling in the current literature makes its behavior difficult to understand and predict. In this study, we present a one-dimensional lubrication model for the dynamics of an EGaIn droplet moving along an inclined plane. Our model incorporates essential physical effects and parameters including oxidation, capillary action, diffusion, gravity, and Marangoni effects. In particular, we incorporate effects of the electric field, both through electric forces and changes in oxidation flux. We model the thin oxide skin of the droplet, which modulates the interfacial surface tension, as an insoluble surfactant at the surface. Oxidation, while observable in the physical setting, cannot be well measured, calling for an alternative method to quantify oxidation flux. Utilizing experimental data, we calibrate system parameters and qualitatively obtain numerical simulation results comparable to experimental observations. Stability analysis was conducted to understand the impacts of physical effects on our model. We find azimuthal curvature to be the main contributor in the process of threading that also promotes the formation of satellite droplets. Our model has demonstrated success in reproducing the observed dynamics of an EGaIn droplet and provides a valuable resource for further investigation and uses of EGaIn.
Presentation Type
Oral Presentation
Document Type
Article
Publication Date
April 2023