What happens when two droplets meet? For simple liquids, they merge into a single larger drop, driven by surface tension. For complex fluids, however, their internal structure and unusual flow properties can make this seemingly simple process much more intricate.
In the Soft Matter group, we investigate the physics of droplet coalescence using ultra-fast imaging, rheology, and advanced image analysis. We explore how viscous and inertial forces govern merging droplets, how surrounding gas and molecular interactions influence the first moments of contact, and how complex fluid properties shape droplet dynamics.
From the first microscopic bridge between two droplets to their complete merging, we aim to understand how fluid properties and interfacial forces determine the dynamics of coalescence.
Selected Publications
Recent insights into droplet dynamics and the behaviour of complex fluids.
A. Deblais, K. Xie, P. Lewin-Jones et al. · Physical Review Fluids · 2025
Combining experiments and numerical modelling, this study reveals how surrounding gas and van der Waals forces influence the earliest moments of droplet merging, including the formation and initial growth of the liquid bridge.
E. Mirzahossein, M. Grzelka & D. Bonn · Soft Matter · 2025
Using real-time, spatially resolved viscosity measurements, researchers uncover how a gel-like surface layer forms during droplet drying and determines the emergence of striking shapes, from coffee rings to buckled structures.
Research contact: Daniel Bonn · d.bonn@uva.nl ↗