Final Report Summary - DROEMU (DROPLETS AND EMULSIONS: DYNAMICS AND RHEOLOGY) The goal of the "Droplets and Emulsions: Dynamics and Rheology (DROEMU)” project is to improve the understanding on the dynamics of multiphase flows in the presence of complex boundary conditions. Beyond the fundamental importance, these problems are also key for a variety of applications, ranging from engineering, food, medical industries to bio-engineering. These problems are intrinsically multiscale: they range from small atomistic scales, involving the motion of contact lines and molecular-hydrodynamical couplings, to larger scales, involving the mesoscopic collective behaviour of emulsions and soft-glassy systems. The DROEMU team has pursued the associated challenging and ambitious questions following a bottom-up/simple-to-complex trajectory and obtained significant advances for the modelling, characterization and control of droplets motion in microfluidic geometries. We designed new operative strategies to control the motion and production of droplets in presence of complex ingredients coming from the walls (chemical patterning and/or geometrical roughness) and/or from the bulk (non-Newtonian effects). A consistent part of the work was devoted to the understanding of the stability properties of droplets in presence of confinement, and the impact of the geometry and complex non-Newtonian bulk properties. We also extended our studies from single-droplet to multi-droplets scenarios, and investigated complex flow properties at the frontier of research on model emulsions: we characterized their rheology, their non-locality, their universality under confinement, and put the finger on the intimate link between plastic dynamics and macroscopic hydrodynamic flow. Finally, we investigated theoretical and numerical fundamental multiscale phenomena connected to contact line dynamics, emerging slip length and molecular-hydrodynamical couplings. Our approach is based on the integration of state-of-the-art numerical schemes based on lattice Boltzmann models with theoretical and phenomenological modelling, validated and supported by experiments.
