Magnetowetting Dynamics of Compound Droplets

Understanding the spreading dynamics of compound droplets is crucial for emerging applications like micromixers, microreactors, and mechano-responsive artificial cells. Integrating magnetic fields expands the potential of these technologies in soft robotics and medical imaging. Despite extensive research on individual droplets, the magnetowetting processes of compound droplets on hydrophobic surfaces remain underexplored. To address this gap, we use a finite element framework to conduct numerical simulations, focusing on the spreading behavior of compound droplets on hydrophobic surfaces under magnetic fields. Our approach is validated against experimental and theoretical paradigms from existing single-droplet studies. Additionally, we verify our model for the temporal evolution of compound droplet wetting in the absence of magnetic fields against existing numerical results. This research systematically explores wetting behaviors and shell fluid disintegration by manipulating key parameters, including magnetic field intensity and inner-to-outer droplet size ratios. These findings have significant implications for enhancing magnetically controlled soft fluidic systems, particularly in digital microfluidics and drug development.