Electrically modulated droplet impingement onto hydrophilic and (super)hydrophobic solid surfaces

Although the impact of impinging droplets on solid substrates has been widely studied, any possible non-trivial interaction between the substrate wettability and applied electric field toward altering the underlying dynamical characteristics remains unexplored. In this study, the interaction between electric field and hydrodynamic transport, toward influencing the dynamic behavior of a water droplet, dispersed in an immiscible fluid, on solid substrates has been numerically investigated. Finite element simulations were performed with a conservative level-set method to track the liquid–liquid interface. The numerical method is first validated with the available experimental data. After ensuring the accuracy of the simulation method, the effects of variations in impact velocity, electric field strength, electric permittivity of the surrounding liquid, and substrate wettability have been studied to clarify the underlying physics of this problem. These results may turn out to be of profound importance toward understanding the functionalities of various practical applications and manipulating the droplet dynamics through surface wettability–electric field interaction over the relevant spatiotemporal scales.