  The spreading of a pure, volatile liquid on a wettable substrate has been
studied in extensive detail. Here we show that the addition of a miscible,
non-volatile liquid can strongly alter the contact line dynamics and the final
liquid deposition pattern. We observe two distinct regimes of behavior
depending on the relative strength of solutal Marangoni forces and surface
wetting. Finger-like instabilities precede the deposition of a sub-micron thick
film for large Marangoni forces and small solute contact angles, whereas
isolated, pearl-like drops emerge and are deposited in quasi-crystalline
patterns for small Marangoni forces and large solute contact angles. This
behavior can be tuned by directly varying the contact angle of the solute
liquid on the solid substrate.

Soft Condensed Matter;Chemical Physics;Fluid Dynamics