Making an impact
Figure 1. (a) An undeformed drop with
diameter Do hits
the surface and spreads out to its
maximum diameter, Dmax,
within the first 2 ms. The drop
subsequently retracts and can either detach
from the surface, as happens for pure
water (b), or remain bound to the
surface, like the polyethyleneoxide
solution (c). A typical photographic
sequence (left to right) of (b) a
drop of pure water and (c) a drop
of dilute polyethyleneoxide solution
striking a smooth hydrophobic surface.
The drop is the uppermost image in
each photograph while the lower
images are reflections from the top
and bottom surfaces of the solid.
See a video clip of the droplets (850 KB, AVI format). The left and right panels of the video clip correspond to parts (b) and (c) of this figure. Click the 'back' button in your browser to return to this page.