The surface and hydrodynamic forces between individual oil droplets in solution can provide insight into both emulsion stability and processes such as drop coalescence in liquid-liquid extraction. We present the first measurements of the interaction forces between alkane droplets in aqueous solution using atomic force microscopy. The radii of the droplets were well below the capillary lengths f...

The effect of storage time on the coalescence stability and drop size distribution of egg yolk (EY) and whey protein concentrate (WPC) stabilized emulsions is studied. The emulsion stability is evaluated by centrifugation, whereas the drop size distribution is measured by means of NMR and optical microscopy. The experimental results show that there is no general relation between the emulsion st...

This work focuses on the study of bulk flows accompanying the coalescence of two aqueous drops, one containing surfactant and the other surfactant-free, in silicone oils of various viscosities. It is observed that the surfactant-free drop intrudes into the surfactant-laden drop in the form of a penetrating jet whose speed increases and average radius decreases with increasing outer phase viscos...

The coalescence of polymer droplets is a fundamental phenomenon which appears for example when mixing two polymers. When two polymeric droplets collide, a transient regime appears, which results from a competition between interfacial and viscoelastic effects : the spherical droplets deform to give birth to a new drop in a short time (tc) and the drop shape stabilizes after a long time. A novel ...

In this study, the recoil and oscillation of single and consecutively printed drops on substrates of different wettabilities are examined using a high speed camera. The results show that, for a droplet impact on a dry surface at Weber number ~ O (1), both inertia and capillary effects are important in the initial spreading regime before the droplet starts to oscillate. For a substrate of higher...

A three-dimensional boundary-integral algorithm is used to study thermocapillary interactions of two deformable drops in the presence of bulk-insoluble, non-ionic surfactant. The primary effect of deformation is to slow down the rate of film drainage between drops in close approach and prevent coalescence in the absence of van der Waals forces. Both linear and non-linear models are used to desc...

The gravity-driven motion of a droplet impacting on a liquid–liquid interface is studied. The full Navier–Stokes equations are solved on a fixed, uniform grid using a finite difference/front-capturing method. For the representation of fluid–fluid interfaces, a coupled Level-Set/Volume-Of-Fluid method [M. Sussman, E.G. Puckett, A coupled Level-Set and Volume-of-Fluid method for computing 3D and ...