Non linear elasticity of foam films made of SDS/dodecanol mixtures.

Foam film elasticity plays a significant role in film drainage and film stability and is thus expected to influence foam dynamical properties. It strongly depends on the foaming solution composition and differs from the interface elasticity measured in unconfined geometries. We use a deformable frame to deform an assembly of five films and we measure the tension and extension of each film.

Cavitation Nuclei Regeneration in a Water-Particle Suspension.

Bubble nucleation in water induced by boiling, gas supersaturation, or cavitation usually originates from preexisting gas cavities trapped into solid defects. Even though the destabilization of such gas pockets, called nuclei, has been extensively studied, little is known on the nuclei dynamic. Here, nuclei of water-particle suspensions are excited by acoustic cavitation, and their dynamic is investigated by monitoring the cavitation probability over several thousand pulses.

Dynamical Coupling between Connected Foam Films: Interface Transfer across the Menisci.

The highly confined flow of the liquid phase, trapped between the gas bubbles, is at the origin of the large effective viscosity of the liquid foams. Despite the industrial relevance of this complex fluid, the foam viscosity remains difficult to predict because of the lack of flow characterization at the bubble scale. Using an original deformable frame, we provide the first experimental evidence of the interface transfer between a compressed film (or a stretched film) and its first neighbor, across their common meniscus.

Dynamic Interaction between a Millimeter-Sized Bubble and Surface Microbubbles in Water.

The coalescence between microbubbles and millimeter-sized bubbles is an elementary process in various industrial applications such as froth flotation and wastewater treatment. Fundamental understanding of the coalescence behavior between two colliding bubbles requires knowledge of water drainage from the thin liquid film between the deformable air-water surfaces, a simple phenomenon with high complexity in physics because of the interplay of surface forces, hydrodynamic drainage, and surface rheology. In this work, we performed simultaneous measurements of the interaction force and spatial thin-film thickness during the collision between a millimeter-sized bubble (radius 1.

Universal wetting transition of an evaporating water droplet on hydrophobic micro- and nano-structures.

Water-repellent, rough surfaces have a remarkable and beneficial wetting property: when a water droplet comes in contact with a small fraction of the solid, both liquid-solid adhesion and hydrodynamic drag are reduced. As a prominent example from nature, the lotus leaf-comprised of a wax-like material with micro- and nano-scaled roughness-has recently inspired numerous syntheses of superhydrophobic substrates. Due to the diverse applications of superhydrophobicity, much research has been devoted to the fabrication and investigations of hydrophobic micro-structures using established micro-fabrication techniques.

A facile sonochemical synthesis of shell-stabilized reactive microbubbles using surface-thiolated bovine serum albumin with the Traut's reagent.

The short lifetime of proteinaceous microbubbles produced using conventional sonication method has hindered their applications in drug delivery and metal removal from wastewater. In this study, we aimed to synthesize stable proteinaceous microbubbles and to demonstrate their reactivity. Our model protein, bovine serum albumin (BSA) was treated with 2-iminothiolane hydrochloride (Traut's reagent) to convert primary amines to thiols before the synthesis of microbubbles.

Cell detachment and label-free cell sorting using modulated surface acoustic waves (SAWs) in droplet-based microfluidics.

We present a droplet-based surface acoustic wave (SAW) system designed to viably detach biological cells from a surface and sort cell types based on differences in adhesion strength (adhesion contrast) without the need to label cells with molecular markers. The system uses modulated SAW to generate pulsatile flows in the droplets and efficiently detach the cells, thereby minimizing the SAW excitation power and exposure time. As a proof of principle, the system shows efficient sorting of HEK 293 from A7r5 cells based on adhesion contrast.