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.

Marangoni Bursting: Evaporation-Induced Emulsification of Binary Mixtures on a Liquid Layer

“…VII [35]). As in many previous studies on dewetting or bursting films [34,41,42], the formation of the rim and its destabilization into droplets are not yet fully understood. A more refined description accounting for inhomogeneous thickness profiles and velocity fields is challenging but beyond the scope of the present work.…”

“…A popular and festive manifestation of these instabilities is the formation of "tears" along the walls of a glass of wine [31,32]. While the evaporation-induced flows of liquids lying on a solid substrate have been extensively studied, the evolution of an evaporating liquid on a nonmiscible fluid layer has only recently received attention [33,34].…”

Evolution of Self‐Propelled Objects: From the Viewpoint of Nonlinear Science

“…[1][2][3][4][95][96][97][98][99][100][101] Most of these studies focus on miniaturization likem icromotors and functionalization such as aJ anus particle. [1][2][3][4][95][96][97][98][99][100][101] Most of these studies focus on miniaturization likem icromotors and functionalization such as aJ anus particle.…”

Thin films in partial wetting: stability, dewetting and coarsening

“…The instability leads to dewetting of the film and formation of drops. Both liquid and solid-state dewetting at the nano-scale are relevant in many phenomena (Blossey 2012;Gentili et al 2012;Thompson 2012;Mukherjee & Sharma 2015; Pierre-Louis 2016) such as pumping liquids using nanowires (Huang et al 2013), patterning via self-assembly (Gau et al 1999;Higgins & Jones 2000;Lopes & Jaeger 2001;Huang et al 2005;Segalman 2005;van Hameren et al 2006;Pokroy et al 2009;Fowlkes et al 2011;Han & Lin 2012;Thiele 2014;Wu et al 2015;Kong et al 2015Kong et al , 2016, synthesis of core-shell nanoparticle arrays (McKeown et al 2015), droplet generation (Yamamoto et al 2015;Keiser et al 2017), needle growth (Yu et al 2013), understanding slip and rheology of nanometric films (Herminghaus et al 2002;Fetzer et al 2005Fetzer et al , 2007aBäumchen & Jacobs 2010;Bäumchen et al 2012;Bäumchen et al 2014;McGraw et al 2014), tear film dynamics (Braun 2012), film flow in heat pipes (Kundan et al 2017), Rayleigh-Plateau instability of nano-wires or liquids in nano-channels (Molares et al 2004;Chen et al 2007), or stability of bubbles/drops in micro/nano-channels (Huerre et al 2015;Hammoud et al 2017).…”