  We study the destabilization mechanism of thin liquid sheets expanding in air
and show that dilute oil-in-water emulsion-based sheets disintegrate through
the nucleation and growth of holes that perforate the sheet. The velocity and
thickness fields of the sheet outside the holes are not perturbed by holes and
hole opening follows a Taylor-Culick law. We find that a pre-hole, which widens
and thins out the sheet with time, systematically precedes the hole nucleation.
The growth dynamics of the pre-hole follows the law theoretically predicted for
a liquid spreading on another liquid of higher surface tension due to Marangoni
stresses. Classical Marangoni spreading experiments quantitatively corroborate
our findings.
