1 research outputs found
Droplet Impact Dynamics on Biomimetic Replica of Yellow Rose Petals: Rebound to Micropinning Transition
Rose petals exhibit a phenomenal wetting property of
being sticky
and superhydrophobic simultaneously. A recent study has shown that
for short timescales, associated with drop impact phenomenon, lotus
leaf and rose petal replicas exhibit similar wettability, thereby
highlighting the difference between long and short time wettability.
Also, short time wetting on rose petals of different colors remains
completely unaddressed, as almost all existing study on wetting of
rose petals have been performed with the classical red rose (Rosa chinensis). In this paper, we compare the drop
impact studies on replicas of a yellow rose petal, with those on extensively
studied red rose petal replicas and the lotus leaf over a wide range
of Weber number (We), by varying the height of fall
(h) from 10 to 375 mm. Our results reveal that over
the replica of a yellow rose petal, the initial impact outcome varies
from complete rebound to micro pinning and eventually complete pinning
depending on the kinetic energy of the impacting drop, in contrast
to that on red rose petal replica on which the droplet always pinned.
Based on experimental finding, we present a comprehensive regime phase
map of the post impact behavior of the drop on different surfaces
as a function of impact height. We also present a simple scaling analysis
to understand the combined effect of pattern height and periodicity
on the critical h corresponding to wetting regime
transition. Additionally, variation of maximum spreading diameter
and spreading time with the h for the different surfaces
is also discussed. The results highlight that the initial impact dynamics
of a water drop over a topographically patterned substrate is a strong
function of the topographical parameters and can be very different
from the equilibrium wetting state