Dr. Niveditha Samudrala, Yale University

"Particles at fluid interfaces: adsorp1on, assembly, and mechanics"

Abstract: Colloidal particles at oil/water interfaces are exploited in various encapsulation & controlled-release technologies relevant in drug delivery, personal care, and food. Here, we use a bottom-up approach to investigate mechanically-driven release of emulsion droplets coated with novel nanoparticles. Starting with amphiphilic dumbbells, we first investigate the surface-active nature and equilibrium configuration of particles at a planar interface. We explain our findings using a simple geometrical model, which is based on intrinsic particle parameters. We then probe the mechanics of particle-laden droplets using micropipette aspiration focusing on the onset of failure and resulting failure modes. We compare our findings to simple cases of bare droplets and molecular surfactant-laden droplets to elucidate the underlying physics. Understanding the mechanics of these particle-laden interfaces would enable their use in controlled-release applications, such as treating a narrowing artery with targeted capsules, and tuning them to have different flow properties.