ThAmeS Multiphase

Abstract This Letter explores the influence of colloids at liquid-liquid interfaces on droplet pinch-off dynamics in microfluidic devices, examining hard polystyrene particles and soft pNIPAM microgels. We uncover a significant deviation in droplet formation time compared to pure systems, similarly to surfactant-laden systems, yet notably, colloids exert minimal impact on droplet size, indicating potential nonlinear effects.

Synergistic effects between a non-ionic and an anionic surfactant on the micellization process and the adsorption at liquid/air surfaces† Predicting the behaviour of solutions with surfactants of significantly different critical micelle concentration (CMC) values remains a challenge. The study of the molecular interactions within micelles and interfaces in surfactant combinations used in everyday products is essential to understand these complex systems.

When a drop merges with its homophase, a liquid cylinder appears in certain conditions, which is pinched off leading to partial coalescence. We investigate the process experimentally and numerically, and find that the Rayleigth-Plateau instability is able to pinch off the cylinder when its height-to-neck ratio exceeds one. Surfactants are found to attenuate the cylinder and produce multiple droplets at moderate concentrations.