Publication
When aliquid drop approaches a flat solid surface, the airbeneath it is compressed,flattening the bottom of the drop andforcing initial contact to occur in aring-shape, trapping a pocketof air in its center as two wetting frontsrapidly expand bothoutward and inwards to completely wet the surface. We combine total internalreflection (TIR) microscopy with anovel virtual frame technique~(VFT) to directly observe the sub-micron lengthscales above asolid surface as the drop approaches, impacts and then spreads~over it.
Athanasios Nenes, Satoshi Takahama, Mária Lbadaoui-Darvas