Solid Beads on Liquid-Infused Materials

It is well-known that ants get trapped in carnivorous pitcher plants, owing to the plant's unique ability to achieve ultra-slippery surfaces. Along this vein, we study the friction on a solid sphere moving on a liquid-infused material. We identify three distinct regimes of motion - sticking, rolling, and bouncing – respectively determined by the existence of a symmetric meniscus, of an asymmetric meniscus (or tail), and by the breaking of this tail. Based on experimental observations, we propose that contrary to the general conception, solids on tilted infused materials do not necessarily slip and fall.