title: The evolution of spatial ordering of oil drops fast spreading on a water surface.
abstract: The design of dynamically self-assembled systems is of high interest in science and technology. Here, we report a unique cascade in the self-ordering of droplets accompanied by a dewetting transition. The dynamic self-emergent droplets are observed when a thin liquid layer of an immiscible fluorocarbon oil (perfluorooctyl bromide, PFOB) is placed on a water surface. Due to the gradual evaporation of PFOB, a circular PFOB-free domain appears as a result of a local dewetting transition. A circular pearling structure is generated at the rim with the growth of the dewetting hole. As the next stage, linear arrays of droplets are generated in a radial manner from the centre of the hole. These one-dimensional arrangements then evolve into two-dimensional hexagonal arrays of microdroplets through collective rhythmical shrinking/expanding motions. The emergence of such dynamic patterns is discussed in terms of the nonlinear kinetics of the dewetting transition under thermodynamically dissipative conditions.
authors.affiliation: Department of Chemical Engineering and Materials Science, Doshisha University, Kyoto 610-0321, Japan.
authors.forename: Daigo
authors.initials: D
authors.lastname: Yamamoto
authors.affiliation: Department of Chemical Engineering and Materials Science, Doshisha University, Kyoto 610-0321, Japan.
authors.forename: Chika
authors.initials: C
authors.lastname: Nakajima
authors.affiliation: Department of Chemical Engineering and Materials Science, Doshisha University, Kyoto 610-0321, Japan.
authors.forename: Akihisa
authors.initials: A
authors.lastname: Shioi
authors.affiliation: Fluorinated Soft Matter Group, Institut Charles Sadron (CNRS), University of Strasbourg, 23 rue du Loess, Strasbourg 67034, France.
authors.forename: Marie Pierre
authors.initials: MP
authors.lastname: Krafft
authors.affiliation: Laboratory of Life Physics, Faculty of Life and Medical Sciences, Doshisha University, Kyoto 610-0394, Japan.
authors.forename: Kenichi
authors.identifier: 0000000227517136
authors.initials: K
authors.lastname: Yoshikawa