Deforming Ice with Drops.

A uniform solidification front undergoes nontrivial deformations when encountering an insoluble dispersed particle in a melt. For solid particles, the overall deformation characteristics are primarily dictated by heat transfer between the particle and the surrounding, remaining unaffected by the rate of approach of the solidification front. In this Letter we show that, conversely, when interacting with a droplet or a bubble, the deformation behavior exhibits entirely different and unexpected behavior.

Correction: Evaporation-driven liquid flow in sessile droplets.

Correction for 'Evaporation-driven liquid flow in sessile droplets' by Hanneke Gelderblom , , 2022, , 8535-8553, https://doi.org/10.1039/D2SM00931E.

Evaporation-driven liquid flow in sessile droplets.

The evaporation of a sessile droplet spontaneously induces an internal capillary liquid flow. The surface-tension driven minimisation of surface area and/or surface-tension differences at the liquid-gas interface caused by evaporation-induced temperature or chemical gradients set the liquid into motion. This flow drags along suspended material and is one of the keys to control the material deposition in the stain that is left behind by a drying droplet.

Evaporation of a Sessile Colloidal Water-Glycerol Droplet: Marangoni Ring Formation.

The transport and aggregation of particles in suspensions is an important process in many physicochemical and industrial processes. In this work, we study the transport of particles in an evaporating binary droplet. Surprisingly, the accumulation of particles occurs not only at the contact line (due to the coffee-stain effect) or at the solid substrate (due to sedimentation) but also at a particular radial position near the liquid-air interface, forming a "ring", which we term as the .

Periodic bouncing of a plasmonic bubble in a binary liquid by competing solutal and thermal Marangoni forces.

The physicochemical hydrodynamics of bubbles and droplets out of equilibrium, in particular with phase transitions, display surprisingly rich and often counterintuitive phenomena. Here we experimentally and theoretically study the nucleation and early evolution of plasmonic bubbles in a binary liquid consisting of water and ethanol. Remarkably, the submillimeter plasmonic bubble is found to be periodically attracted to and repelled from the nanoparticle-decorated substrate, with frequencies of around a few kilohertz.

Marangoni Instability of a Drop in a Stably Stratified Liquid.

Marangoni instabilities can emerge when a liquid interface is subjected to a concentration or temperature gradient. It is generally believed that for these instabilities bulk effects like buoyancy are negligible compared to interfacial forces, especially on small scales. Consequently, the effect of a stable stratification on the Marangoni instability has hitherto been ignored.

Evaporating droplets on oil-wetted surfaces: Suppression of the coffee-stain effect.

The evaporation of suspension droplets is the underlying mechanism in many surface-coating and surface-patterning applications. However, the uniformity of the final deposit suffers from the coffee-stain effect caused by contact line pinning. Here, we show that control over particle deposition can be achieved through droplet evaporation on oil-wetted hydrophilic surfaces.

Bouncing Oil Droplet in a Stratified Liquid and its Sudden Death.

Droplets can self-propel when immersed in another liquid in which a concentration gradient is present. Here we report the experimental and numerical study of a self-propelling oil droplet in a vertically stratified ethanol-water mixture: At first, the droplet sinks slowly due to gravity, but then, before having reached its density matched position, jumps up suddenly. More remarkably, the droplet bounces repeatedly with an ever increasing jumping distance, until all of a sudden it stops after about 30 min.

Gravitational Effect in Evaporating Binary Microdroplets.

The flow in an evaporating glycerol-water binary submillimeter droplet with a Bond number Bo≪1 is studied both experimentally and numerically. First, we measure the flow fields near the substrate by microparticle image velocimetry for both sessile and pendant droplets during the evaporation process, which surprisingly show opposite radial flow directions-inward and outward, respectively. This observation clearly reveals that in spite of the small droplet size, gravitational effects play a crucial role in controlling the flow fields in the evaporating droplets.

Self-propulsion of inverse Leidenfrost drops on a cryogenic bath.

When deposited on a hot bath, volatile drops are observed to stay in levitation: the so-called Leidenfrost effect. Here, we discuss drop dynamics in an inverse Leidenfrost situation where room-temperature drops are deposited on a liquid-nitrogen pool and levitate on a vapor film generated by evaporation of the bath. In the seconds following deposition, we observe that the droplets start to glide on the bath along a straight path, only disrupted by elastic bouncing close to the edges of the container.

Evaporation-Triggered Segregation of Sessile Binary Droplets.

Droplet evaporation of multicomponent droplets is essential for various physiochemical applications, e.g., in inkjet printing, spray cooling, and microfabrication.

Self-wrapping of an ouzo drop induced by evaporation on a superamphiphobic surface.

Evaporation of multi-component drops is crucial to various technologies and has numerous potential applications because of its ubiquity in nature. Superamphiphobic surfaces, which are both superhydrophobic and superoleophobic, can give a low wettability not only for water drops but also for oil drops. In this paper, we experimentally, numerically and theoretically investigate the evaporation process of millimetric sessile ouzo drops (a transparent mixture of water, ethanol, and trans-anethole) with low wettability on a superamphiphobic surface.

Evaporation-triggered microdroplet nucleation and the four life phases of an evaporating Ouzo drop.

Evaporating liquid droplets are omnipresent in nature and technology, such as in inkjet printing, coating, deposition of materials, medical diagnostics, agriculture, the food industry, cosmetics, or spills of liquids. Whereas the evaporation of pure liquids, liquids with dispersed particles, or even liquid mixtures has intensively been studied over the past two decades, the evaporation of ternary mixtures of liquids with different volatilities and mutual solubilities has not yet been explored. Here we show that the evaporation of such ternary mixtures can trigger a phase transition and the nucleation of microdroplets of one of the components of the mixture.