Invasion of a magnetic-bead-laden droplet placed over a hole in the presence of a magnetic field
Phys. Rev. E 113, 035102 – Published 11 March, 2026
DOI: https://doi.org/10.1103/b4dc-hkm3
Abstract
How a magnetic-bead-laden droplet is manipulated by a magnetic field remains a challenging topic of quantitative investigation. In this paper, we propose a theoretical model to investigate the equilibrium states of a magnetic-bead-laden droplet placed over either a bottomed superhydrophobic cylindrical hole or a bottomless one in the presence of an external magnetic field. The position, the contact angle, and the deflection angle of the droplet in equilibrium are obtained for the two systems by applying the principle of energy minimization. Two phase diagrams are constructed correspondingly for the two cases. It is found that a loss of stability exists, leading to a slipping off of the droplet down the bottomless hole.
