1ILM - Institut Lumière Matière [Villeurbanne] (UMR5306 CNRS Université Claude Bernard Lyon 1 Domaine Scientifique de La Doua Bâtiment Kastler, 10 rue Ada Byron 69622 Villeurbanne CEDEX, Franc - France)
Abstract : We report on the observation of thin salt shells that form at the periphery of evaporating pure water drops on salt. Shell shapes range from rings of inclined walls to hollow toroidal rims. We interpret this phenomenon as a consequence of a molecular coffee-stain effect by which the dissolved salt is advected toward the pinned contact line where an increased evaporation takes place. The subsequent salt supersaturation in the vicinity of the triple line drives the crystallization of the shell at the liquid-air interface. This interpretation is supported by a simple model for shell growth.
A. Mailleur, C. Pirat, Olivier Pierre-Louis, J. Colombani. Hollow Rims from Water Drop Evaporation on Salt Substrates. Physical Review Letters, American Physical Society, 2018, 121 (21), pp.214501. ⟨10.1103/PhysRevLett.121.214501⟩. ⟨hal-02290270⟩