Coalescence Dynamics of Particle-Laden Bubbles

Understanding the coalescence of particle-laden bubbles is crucial to our understanding of the role of particles in stabilizing liquid foams. In this work, the coalescence of microparticle-laden bubbles is studied experimentally using high-speed photography. In particular, the interparticle forces in the neck region during the early stage of bubble coalescence are calculated. The results indicate that a monolayer of silica particles coating the bubble surfaces hinders the growth dynamics of the air neck formed between the coalescing bubbles. We postulate that the decrease in the growth dynamics is due to the surface pressure caused by the particle interaction after the initiation of bubble coalescence. We identify that the apparent surface tension in the neck region increases with time for particle-laden bubbles and is lower for larger particle sizes. These findings enhance our understanding of the role of particles on the dynamics of fast deforming interfaces.