We actuate with light & magnets, we fold & unfold DNA, we cell-free express proteins, we play with drops, marbles & interfaces, we organize particles, we harness coffee rings.

Our new paper "Liquid-liquid coffee-ring effect" accepted in Journal of Colloids and Interface Science!

Abstract: The so-called coffee-ring effect (CRE) is extraordinarily common, problematic in industry and attractively puzzling for researchers, with the accepted rule that it requires two key-ingredients: solvent evaporation and contact line pinning. Here, we demonstrate that the CRE also occurs when the solvent of a pinned sessile drop transfers into another liquid, without involving any evaporation. We show that it shares all characteristic features of the evaporative CRE: solvent transfer-driven transport of solutes to the contact line, ring-shaped deposit, closely-packed particle organization at the contact line, and sizedependent particle sorting. We thus suggest expanding the definition of the coffee-ring effect to any pinned drop having its solvent transferring to an outer medium where the drop compounds cannot be dissolved.

Liquid-liquid coffee-ring effect
V. Poulichet, M. Morel, S. Rudiuk, D. Baigl*
J. Colloid. Interf. Sci. 2020, 573, 370-375
   -doi : 10.1016/j.jcis.2020.03.094