Subpatterns of Thin-Sheet Splash of a Droplet Impact on a Heated Surface

A thin-sheet splash of a droplet impact on a solid surface typically appears as secondary droplets are ejected from a levitated liquid lamella. A recent work (Qin, M.; Tang, C.; Guo, Y.; Zhang, P.; Huang, Z., Langmuir 2020, 36 (18), 4917-4922) identified three subpatterns of a thin-sheet splash on a smooth wall at room temperature (T0). In the present work concerning the high-temperature (TW) surface, we show that subpatterns of the thin-sheet splash can be unified in the three-dimensional phase diagram of Oh-We-TW, where Oh is the Ohnesorge number and We is the Weber number. As TW is sufficiently high, the Leidenfrost effect becomes so prominent that both deposition and thin-sheet splash make a transition to Leidenfrost breakup. For the transition surface temperature TW,cr from thin-sheet splash to deposition, a scaling correlation of TW,cr/T0 ∼We3/2 is derived based on the analysis of the temperature-dependent destabilizing force on the levitated lamella and agrees well with our experimental data.