Static Friction of Liquid Marbles
Phys. Rev. Lett. 137, 054001 – Published 30 July, 2026
DOI: https://doi.org/10.1103/njnj-yhc6
Abstract
Liquid marbles, droplets coated with a granular layer, are highly mobile as particles prevent capillary adhesion to the substrate. Yet their coating creates a static rolling friction, which we measure and model. Motion requires shear within the shell so that it is governed mainly by the grain density. This density controls yielding via a logistic function emerging as the particle network approaches percolation and increasing rapidly at close packing. More broadly, our system offers a simple platform for probing granular raft mechanics and measuring their effective surface tension.
