title: Light-Driven Transport of a Liquid Marble with and against Surface Flows.
abstract: Liquid marbles, that is, liquid drops coated by a hydrophobic powder, do not wet any solid or liquid substrate, making their transport and manipulation both highly desirable and challenging. Herein, we describe the light-driven transport of floating liquid marbles and emphasize a surprising motion behavior. Liquid marbles are deposited on a water solution containing photosensitive surfactants. Irradiation of the solution generates photoreversible Marangoni flows that transport the liquid marbles toward UV light and away from blue light when the thickness of the liquid substrate is large enough (Marangoni regime). Below a critical thickness, the liquid marbles move in the opposite direction to that of the surface flow at a speed increasing with decreasing liquid thickness (anti-Marangoni). We demonstrate that the anti-Marangoni motion is driven by the free surface deformation, which propels the non-wetting marble against the surface flow. We call this behavior "slide effect".
authors.affiliation: Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department of Chemistry, PASTEUR, 24 rue Lhomond, 75005, Paris, France.|Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France.
authors.forename: Nikita
authors.initials: N
authors.lastname: Kavokine
authors.affiliation: Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department of Chemistry, PASTEUR, 24 rue Lhomond, 75005, Paris, France.|Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France.
authors.forename: Manos
authors.initials: M
authors.lastname: Anyfantakis
authors.affiliation: Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department of Chemistry, PASTEUR, 24 rue Lhomond, 75005, Paris, France.|Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Morel
authors.affiliation: Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department of Chemistry, PASTEUR, 24 rue Lhomond, 75005, Paris, France.|Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France.
authors.forename: Sergii
authors.initials: S
authors.lastname: Rudiuk
authors.affiliation: Université de Bordeaux, Laboratoire Ondes et Matière d'Aquitaine, CNRS UMR 5798, 33405, Talence, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bickel
authors.affiliation: Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Department of Chemistry, PASTEUR, 24 rue Lhomond, 75005, Paris, France. damien.baigl@ens.fr.|Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS, PASTEUR, 75005, Paris, France. damien.baigl@ens.fr.
authors.forename: Damien
authors.initials: D
authors.lastname: Baigl
keywords: Marangoni flows; interfaces; liquid marbles; photoactuation; surface tension