title: Dynamics and universal scaling law in geometrically-controlled sessile drop evaporation.
abstract: The evaporation of a liquid drop on a solid substrate is a remarkably common phenomenon. Yet, the complexity of the underlying mechanisms has constrained previous studies to spherically symmetric configurations. Here we investigate well-defined, non-spherical evaporating drops of pure liquids and binary mixtures. We deduce a universal scaling law for the evaporation rate valid for any shape and demonstrate that more curved regions lead to preferential localized depositions in particle-laden drops. Furthermore, geometry induces well-defined flow structures within the drop that change according to the driving mechanism. In the case of binary mixtures, geometry dictates the spatial segregation of the more volatile component as it is depleted. Our results suggest that the drop geometry can be exploited to prescribe the particle deposition and evaporative dynamics of pure drops and the mixing characteristics of multicomponent drops, which may be of interest to a wide range of industrial and scientific applications.
authors.affiliation: Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Sáenz
authors.affiliation: Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
authors.forename: A W
authors.initials: AW
authors.lastname: Wray
authors.affiliation: Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
authors.forename: Z
authors.initials: Z
authors.lastname: Che
authors.affiliation: Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
authors.forename: O K
authors.initials: OK
authors.lastname: Matar
authors.affiliation: School of Engineering, The University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3FB, UK.
authors.forename: P
authors.identifier: 0000-0003-4917-8283
authors.initials: P
authors.lastname: Valluri
authors.affiliation: Department of Mechanical Engineering, The University of Maryland, College Park, Maryland 20742, USA.
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.affiliation: School of Engineering, The University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3FB, UK.|Tianjin Key Lab of Refrigeration Technology, Tianjin University of Commerce, Tianjin City 300134, China.
authors.forename: K
authors.initials: K
authors.lastname: Sefiane