Surface morphology of drying latex films: Multiple ring formation

When a drop of aqueous solution containing suspended particles dries, particles accumulate at the contact line. Often the contact line undergoes a sequence of pinning-depinning events with particles accumulating whenever the contact line is pinned. These processes lead to ring formation, the details of which are examined here. In particular, we provide detailed measurements of ring formation as a function of the drop radius and the size of the suspended particles, and we report measurements of the time dependence of the essentially stochastic pinning-depinning cycles of the contact line motion.