Drop impact on viscous liquid films

When a liquid drop falls on solid substrate, the air layer between them delays occurrence of liquid–solid contact. For impacts smooth substrates, film can even prevent wetting, allowing to bounce off with dynamics identical that observed for superamphiphobic materials. In this paper, we investigate similar bouncing phenomena, occurring viscous films, mimic atomically goal probe their effective repellency. We elucidate mechanisms associated non-bouncing (floating) transition using experiments, simulations, and minimal model predicts main characteristics impact, contact time coefficient restitution. case highly or very thin impact is not affected by presence film. Within substrate-independent limit, suppressed once viscosity exceeds critical value, as substrates. thicker less both properties influence rebound conspire inhibit above thickness. This substrate-dependent regime also admits low-viscosity drops, in which alone determine limits