Adsorption of Ellipsoidal Particles at Liquid–Liquid\nInterfaces

Abstract

The\nadsorption of particles at liquid–liquid interfaces\nis of great scientific and technological importance. In particular,\nfor nonspherical particles, the capillary forces that drive adsorption\nvary with position and orientation, and complex adsorption pathways\nhave been predicted by simulations. On the basis of the latter, it\nhas been suggested that the timescales of adsorption are determined\nby a balance between capillary and viscous forces. However, several\nrecent experimental results point out the role of contact line pinning\nin the adsorption of particles to interfaces and even suggest that\nthe adsorption dynamics and pathways are completely determined by\nthe latter, with the timescales of adsorption being determined solely\nby particle characteristics. In the present work, the adsorption trajectories\nof model ellipsoidal particles are investigated experimentally using\ncryo-SEM and by monitoring the altitudinal orientation angle using\nhigh-speed confocal microscopy. By varying the viscosity and the viscosity\njump across the interfaces, we specifically interrogate the role of\nviscous forces.