  The Leidenfrost effect, namely the levitation and hovering of liquid drops on
hot solid surfaces, generally requires a sufficiently high substrate
temperature to activate the intense liquid vaporization. Here we report the
agile modulations of Leidenfrost-like prompt jumping of sessile water
microdroplets on micropillared surfaces at a remarkably mitigated temperature.
Compared to traditional Leidenfrost effect occurring above 230 {\deg}C, the
fin-array-like micropillars enables Wenzel-state water microdroplets to
levitate and jump off within 1.33 ms at an unprecedently low temperature of 130
{\deg}C by triggering the inertia-controlled growth of individual vapor bubbles
at the droplet base. We demonstrate that droplet jumping, resulting from the
momentum interactions between the expanding vapor bubble and the droplet, can
be deftly modulated by simply tailoring the thermal boundary layer thickness
via pillar heights, which acts to regulate the bubble expansion between the
inertia-controlled mode and the heat-transfer-limited mode. Intriguingly, the
two bubble growth modes give rise to distinct droplet jumping behaviors
characterized by constant velocity and constant energy schemes, respectively.
This strategy allows the facile purging of wetting liquid drops on rough or
structured surfaces in a controlled manner, inspiring promising applications in
rapid removal of fouling even settled in surface cavities.
