Contact-line pinning and dynamic friction are fundamental forces that oppose the motion of droplets on solid surfaces. Everyday experience suggests if a surface offers low contact-line pinning, it will also impart relatively to moving droplet. Examples such surfaces superhydrophobic, slippery porous liquid-infused, lubricant-impregnated Here, however, we show omniphobic covalently attached liquid-like (SOCAL) have remarkable combination contact-angle hysteresis properties, which lead very...

We demonstrate the transport and positioning of water droplets on macro-patterned lubricant-impregnated surfaces. The macro-patterning produces menisci features in impregnating liquid layer which interact with a droplet via capillary mechanism similar to Cheerios effect. These interactions control motion an otherwise completely slippery surface. present experimental results using V-shape channel geometry as model system. interaction between deformations lubricant induced by underlying leads...

Multiphase numerical simulations have become a widely sought methodology for modelling capillary flows due to their scientific relevance and multiple industrial applications. Much progress has been achieved using different approaches, the volume of fluid is one most popular methods used two or more phases its simplicity, accuracy robustness. However, when prescribing forces emerging from three fluid-fluid interfaces, force balance not guaranteed can lead spurious self-propulsion. Here, new...

Abstract Droplet evaporation on solid surfaces is important in many applications including printing, micro-patterning and cooling. While seemingly simple, the configuration of evaporating droplets solids difficult to predict control. This because typically proceeds as a “stick-slip” sequence—a combination pinning de-pinning events dominated by static friction or “pinning”, caused microscopic surface roughness. Here we show how smooth, pinning-free, non-planar topography promote different...

Spontaneous capillary imbibition is a classical problem in interfacial fluid dynamics with broad range of applications, from microfluidics to agriculture. Here we study the duration cross-over between an initial linear growth front diffusive-like limit Washburn's law. We show that local-resistance sources, such as inertial resistance and friction caused by advancing meniscus, always motion imbibing front. Both effects give rise exponent regimes. how this much longer than previously thought –...

When a voltage difference is applied between conducting liquid and (solid) electrode, the observed to spread on solid. This phenomenon, generally referred as electrowetting, underpins number of interfacial phenomena interest in applications that range from droplet microfluidics optics. Here, we present lattice-Boltzmann method can simulate coupled hydrodynamics electrostatics equations motion two-phase fluid means model electrowetting phenomena. Our has advantage modeling electrostatic...

We demonstrate the continuous translational invariance of energy a capillary surface in contact with reconfigurable solid boundaries. present theoretical approach to find energy-invariant equilibria spherical surfaces boundaries arbitrary shape and examine implications dynamic frictional forces upon reconfiguration Experimentally, we realize our ideas by manipulating position droplet wedge geometry using lubricant-impregnated surfaces, which eliminate contact-angle hysteresis provide test...

The motion of confined droplets in immiscible liquid-liquid systems strongly depends on the intrinsic relative wettability liquids confining solid material and typical speed, which can induce formation a lubricating layer continuous phase. In electrowetting, routinely makes use aqueous drops ambient non-polar fluids that wet wall material, electric stresses enter force balance addition to capillary viscous forces confinement effects. Here, we study mobility upon electrowetting actuation...

Abstract The motion of droplets on solid surfaces in response to an external gradient is a fundamental problem with broad range applications, including water harvesting, heat exchange, mixing and printing. Here we study the driven by humidity gradient, i.e. variation concentration their own vapour surrounding gas phase. Using lattice-Boltzmann simulations diffuse-interface hydrodynamic model account for liquid phases, demonstrate that droplet migrates towards region higher concentration....

Abstract The breakup of a slender filament liquid driven by surface tension is classical fluid dynamics stability problem that important in many situations where fine droplets are required. When the resting on flat solid which imposes wetting conditions subtle interplay with makes instability pathways and mode selection difficult to predict. Here, we show how controlling static dynamic can lead repeatable switching between toroidal film an electrically insulating patterns well-defined...

We present a theoretical study of the statics and dynamics partially wetting liquid droplet, equilibrium contact angle $\unicode[STIX]{x1D703}_{e}$ , confined in solid wedge geometry opening $\unicode[STIX]{x1D6FD}$ . focus on mostly non-wetting regime, given by condition $\unicode[STIX]{x1D703}_{e}-\unicode[STIX]{x1D6FD}>90^{\circ }$ where droplet forms barrel – closed shape positive mean curvature. Using quasi-equilibrium assumption for liquid–gas interface, we compute changes to...

We study the relaxation towards equilibrium of a liquid barrel-a partially wetting droplet in wedge geometry-using diffuse-interface approach. formulate hydrodynamic model motion barrel framework Navier-Stokes and Cahn-Hilliard equations motion. present lattice-Boltzmann method to integrate equations, where we introduce an algorithm dynamic on smooth solid boundaries. simulation results over-damped dynamics barrel. find that droplets is driven by capillary forces damped friction forces. show...

The collision of binary droplets plays a key role in several industrial, chemical and biological processes. In these processes, the quality desired outcome is strongly dependent on mixing liquid as they collide mid-air. this work, multiphase direct numerical simulations based volume-of-fluid method have been used to investigate process analyse effects parameters such injection velocity, timing angles. evolution due convection irreversible diffusive processes has quantified by means...

Abstract The study of suspended binary droplet collisions is an active research topic that has gathered interest due to its complexity and industrial applications such as bioprinting. For many techniques rely on the collision two droplets, quality outcome depends mixing process begins when droplets come in contact with each other. In this work, we how difference material properties colliding viscosity surface tension, influence process. Employing multiphase direct numerical simulations,...

The shape and stability of a droplet in contact with solid surface is affected by the chemical composition topography solid, crucially, droplet's size. During variation size, most often observed during evaporation, droplets on smooth patterned surfaces can undergo sudden position changes. Such changes, called snaps, are prompted pattern arise from fold pitchfork bifurcations which respectively cause symmetric asymmetric motions. Yet, type snap likely to be an open fundamental question that...

Abstract The study of suspended binary droplet collisions is an active research topic that has gathered interest due to its complexity and industrial applications such as bioprinting. For many techniques rely on the collision two droplets, quality outcome depends mixing process begins when droplets come in contact with each other. In this work, we how difference material properties colliding viscosity surface tension, affect process. Employing multiphase direct numerical simulations,...

The dynamic effect of an electric field on dielectric liquids is called liquid dielectrophoresis. It widely used in several industrial and scientific applications, including inkjet printing, microfabrication, optical devices. Numerical simulations liquid-dielectrophoresis are necessary to understand the fundamental physics phenomenon, but also explore situations that might be difficult or expensive implement experimentally. However, such modeling challenging, as one needs solve electrostatic...

The study of suspended binary droplet collisions is an active research topic that has gathered interest due to its complexity and industrial applications such as bioprinting. For many techniques rely on the collision two droplets, quality outcome depends mixing process begins when droplets come in contact with each other. In this work, we how difference material properties, viscosity surface tension, influence process. Employing multiphase direct numerical simulations, distribution impinging...

Multiphase numerical simulations have become a widely sought methodology for modelling capillary flows due to their scientific relevance and multiple industrial applications. Much progress has been achieved using different approaches the volume of fluid is one most popular methods which used two or more phases its simplicity, accuracy robustness. However, when prescribing forces emerging from three fluid-fluid interfaces, force balance not guaranteed can lead spurious self-propulsion. Here,...

The study of suspended binary droplet collisions is an active research topic that has gathered interest due to its complexity and industrial applications such as bioprinting. For many techniques rely on the collision two droplets, quality outcome depends mixing process begins when droplets come in contact with each other. In this work, we how difference material properties, viscosity surface tension, influence process. Employing multiphase direct numerical simulations, distribution impinging...

We present a lattice-Boltzmann method that can simulate the coupled hydrodynamics and electrostatics equations of motion two-phase fluid as means to model electrowetting phenomena. Our has advantage modelling electrostatic fields within algorithm itself, eliminating need for hybrid method. validate our by reproducing static equilibrium configuration droplet subject an applied voltage show apparent contact angle drop depends on following Young-Lippmann equation up angles $\approx 50^\circ$....