title: How faceted liquid droplets grow tails.
abstract: Liquid droplets, widely encountered in everyday life, have no flat facets. Here we show that water-dispersed oil droplets can be reversibly temperature-tuned to icosahedral and other faceted shapes, hitherto unreported for liquid droplets. These shape changes are shown to originate in the interplay between interfacial tension and the elasticity of the droplet's 2-nm-thick interfacial monolayer, which crystallizes at some T = Ts above the oil's melting point, with the droplet's bulk remaining liquid. Strikingly, at still-lower temperatures, this interfacial freezing (IF) effect also causes droplets to deform, split, and grow tails. Our findings provide deep insights into molecular-scale elasticity and allow formation of emulsions of tunable stability for directed self-assembly of complex-shaped particles and other future technologies.
authors.affiliation: Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel;
authors.forename: Shani
authors.initials: S
authors.lastname: Guttman
authors.affiliation: Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel;
authors.forename: Zvi
authors.initials: Z
authors.lastname: Sapir
authors.affiliation: Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel;
authors.forename: Moty
authors.initials: M
authors.lastname: Schultz
authors.affiliation: Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel;
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Butenko
authors.affiliation: Condensed Matter Physics & Materials Sciences, Brookhaven National Laboratory, Upton, NY 11973.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Ocko
authors.affiliation: Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel;
authors.forename: Moshe
authors.initials: M
authors.lastname: Deutsch
authors.affiliation: Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002, Israel; eli.sloutskin@biu.ac.il.
authors.forename: Eli
authors.initials: E
authors.lastname: Sloutskin
keywords: emulsions; membranes' buckling; spontaneous emulsification; topological defects; two-dimensional crystals