A Leidenfrost drop forms when a volatile liquid is brought in contact with very hot solid. Then, vapor film comes between the solid and drop, giving to latter appearance of pearl. After brief description shape we show that its size cannot exceed certain value. describe characteristics layer on which it floats. We how related size, both vary time, as evaporation takes place. finally deduce scaling laws for lifetime these drops.

We describe the first steps of spreading a liquid droplet brought in contact with solid that it wets completely. Usually, is assumed dynamics results from balance between forces and viscosity. But before this classical stage, inertia resists to motion, which leads very different dynamic law. study experimentally nature law, compare our recent theoretical predictions, determine duration inertial regime.

We study the electrophoretic blockades due to entries of partially unfolded proteins into a nanopore as function concentration denaturing agent. Short and long pore are observed by electrical detection. passage completely proteins, their frequency increases agent increases, following sigmoidal denaturation curve. Long reveal folded conformations. Their duration more folded. The observation Vogel-Fulcher law suggests glassy behavior.

A drop of low viscosity hitting a solid may bounce, provided that the material is highly hydrophobic. As model such situation, we consider here case very hot solid. Then, as discovered by Leidenfrost, thin layer vapour sustains drop, preventing any contact with substrate. On solid, rebounds, and discuss elasticity shock. Two different cases are described: at large velocity, weaker impact elasticity; small quasi-elastic regime found. The boundary between two domains set Weber number, which...

Ion transport through nanopores drilled in thin membranes is central to numerous applications, including biosensing and ion selective membranes. This paper reports experiments, numerical calculations, theoretical predictions demonstrating an unexpectedly large ionic conduction solid-state nanopores, taking its origin anomalous entrance effects. In contrast naive expectations based on analogies with electric circuits, the surface conductance inside nanopore shown perturb three-dimensional...

Despite the fact that superhydrophobic surfaces possess useful and unique properties, their practical application has remained limited by durability issues. Among those, wetting transition, whereby a surface gets impregnated liquid permanently loses its superhydrophobicity, certainly constitutes most limiting aspect under many realistic conditions. In this study, we revisit so-called Cassie-to-Wenzel transition (CWT) broadly encountered situation of drop impact. Using model hydrophobic...

Osmosis across membranes is intrinsically associated with the concept of semipermeability. Here, however, we demonstrate that osmotic flow can be generated by solute gradients nonselective, fully permeable nanochannels. Using a fluorescence imaging technique, are able to measure water rate inside single nanochannels an unprecedented sensitivity femtoliters per minute rates. Our results indicate onset convective liquid motion under salinity gradients, from higher lower electrolyte...

Abstract Recent advances in the coalescence liquid foams are reviewed, with a special focus on multiscale structure of foams. Studies concerning stability isolated foam films, one hand, and process macroscopic foams, other not always good agreement. This discrepancy reveals that two routes can induce foam. The first route is thermodynamic shows governed by stochastic rupture films. second relies mechanically induced due to spontaneous evolution From literature review, evaluation different...

The stability of foam is investigated experimentally through coalescence events. Instability (coalescence) occurs when the system submitted to external perturbations (T1) and liquid amount in film network below a critical value. Microscopically, transient thick films are observed during rearrangements. Film rupture, with eventual collapse foam, available local too small for be formed. Similar experiments results shown two-bubble case.

The mechanical properties of particle laden interfaces are investigated by studying capillary wave propagation along the interface. Interfaces coated with monodisperse silica hydrophobic particles diameters ranging from 35 μm to 159 μm. surfaces prepared a density just above that required for random close packing, so no macroscopic wrinkles can be observed. Measurements celerity versus wavelength and comparison results theory allow us define stretching modulus bending stiffness such an These...

Abstract The shape of impacting drops onto a solid surface is investigated by probing the local flow velocity and thickness profile spreading lamella during drop impact. First, as model situation no viscous coupling between liquid substrate, impact hot plates, above Leidenfrost temperature, considered. In this case, we demonstrate that profiles are in good agreement with inviscid convective theory. This description allows us to revisit modelling well-studied global behaviour such spreading....

We study experimentally the dynamics of strain-induced T1 neighbour switching in clusters 3D bubbles. To determine physico-chemical processes that set time scale such rearrangements, foaming solutions a wide range well characterized bulk and interfacial rheological properties are used. At low strain rates, is by balance between surface tension viscous forces, we present simple physical model explains these findings, on basis previous experimental theoretical work with 2D foams.1 higher...

Armored interfaces refer to fluid on which a compact monolayer of particles is adsorbed. In this paper, we probe their robustness under impact. For such an investigation, the impact drop (covered or not by particles) flat armored interface considered. Two regimes are observed: small drops impacting at low velocities do coalesce, while bigger falling higher lead coalescence. The coalescence occurs when has just reached its maximum extension directly results from formation bare regions within...

Liquid marbles are liquid droplets covered with hydrophobic particles. This particular layer physically isolates them from the substrate on which they deposited. In this study, we investigate properties of such when impacting onto a solid substrate. The different behaviors during impact (non-bouncing, bouncing and rupture) experimentally characterized scenarios for understanding transitions between three regimes proposed. Eventually, highlight importance particle surface coverage by...

Electrokinetic effects offer a method of choice to control flows in micro and nanofluidic systems. While rather clear picture these phenomena exists now for the liquid-solid interfaces, case liquid-air interfaces remains largely unexplored. Here we investigate at molecular level electrokinetic transport liquid film covered with ionic surfactants. We find that zeta potential, quantifying amplitude effects, depends on surfactant coverage an unexpected way. First, it increases upon lowering...

Drop impacts on a smooth plate heated above the Leidenfrost temperature are investigated in range of large Weber number. Liquid fragmentation due to rupture expanding lamella during impact—by hole nucleation and subsequent growth—is studied. Control this rupturing process is achieved experimentally through use single model-defects attached substrate which act as an initiating spots for formation, whereas liquid does not contact substrate. Overall, shown take place critical impact velocity,...

We investigate the entrance of single poly(ethylene glycol) chains into an $\ensuremath{\alpha}$-hemolysin channel. detect frequency and duration current blockades induced by large neutral polymers, where chain radius is larger than pore diameter. In semidilute regime, these pass only if monomer concentration a well-defined threshold. Experiments are performed in very domain molecular mass, up to $35%$ 200 kDa, respectively, which was previously unexplored. The variation dwell time as...

We investigate experimentally the electrokinetic properties of soft nanofluidic channels that consist in soap films with nanometric thickness, covered charged surfactants. Both electric and fluidic responses system are measured under an applied voltage drop along film. The field is shown to induce electro-osmotic hydrodynamic flow However, contrast systems confined between solid surfaces, nature nanochannel results furthermore a thickening This effect accordingly increases total rate, which...

The velocity of a falling raindrop depends on its size, and thus so does shape. Here we describe the different simple shapes which model drops in air. While millimetric remain spherical, owing to action surface tension, larger than capillary length get flattened, as sessile solids. Air penetrates still globules, are observed be unstable. They inflate till they burst, generating myriads fragments.

Abstract T1 topological rearrangement, i.e. switching of neighbouring bubbles in a liquid foam, is the elementary process foam dynamics, and it involves film disappearance generation. It has been studied extensively as crucial rheology or collapse. dynamics depends mainly on surfactants used to generate several models taking into account surface viscosity and/or elasticity have proposed. By performing experiments cubic assembly films, we go step forward this global analysis investigate...