Experimental investigation of contact time of bouncing droplet on vibrating substrates

The observation of an elastic substrate self-driving droplet to produce a "springboard effect" provides new enlightenment to the application of elastic materials in the anti-icing area. The droplet-substrate dynamic of a water drop impacting a superhydrophobic elastic substrate is experimentally investigated at different Weber (We) numbers and beam stiffness. For water drop, the spreading dynamic is not affected by the We number and beam stiffness since the inertial action is dominant, and the elastic action of the beam is relatively small, while the receding dynamic is closely related to the parameters. For elastic substrate, the vibrating deflection increases with the increase in the We number and reduction of the stiffness, while the vibrating frequency is only dependent on its stiffness. Based on this, the rebound dynamic of the droplet is discovered dependent on the scale relationship between the droplet and substrate oscillation period. Finally, a relation of the contact time of a droplet impacting elastic substrates, which is verified to hold for a large range of We numbers, beam stiffness, and droplet sizes, is established. The discoveries may contribute to the design of a droplet-elastic substrate system to achieve desirable contact time, providing a theoretical basis to forecast the performance of droplet-substrate systems by employing elastic materials.