Controlled Stretching and Splitting of Liquid‐Metal Droplets Under Magnetic Fluidic Coupling

Precise manipulation of liquid metal (LM) droplets for reconfigurable soft electronics and robotics attracts increasing attention, however, highly control on their topological transitions remains a challenge due to their high surface tension. Here we establish a comprehensive computational and experimental framework to facilitate magneto‐mechanical manipulation of Fe‐EGaIn droplets, specifically focusing on the transition from stable elongation to binary fission. A multiphysics phase‐field model is developed to capture the coupling between non‐uniform magnetic fields and interfacial multiphase hydrodynamics. Systematic parametric analyses reveal that the droplet's dynamic fate is governed by the competition among magnetic driving stress, capillary restoring pressure, and hydrodynamic drag. Specifically, interfacial tension determines the thermodynamic energy barrier for breakup, while viscosity acts as a kinetic governor, leading to a “kinetic entrapment” effect that inhibits fission in high‐viscosity regimes. These theoretical predictions are validated by experiments performed in a range of solvent environments. The results demonstrate that modulating the solvent interface could serve as an effective strategy to program droplet topologies under identical magnetic loading. This work offers a quantitative pathway for designing programmable liquid metal architectures driven by environmental‐magnetic coupling.