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Static Friction of Liquid Marbles
Yui Takai1, Kei Mukoyama1, Pritam Kumar Roy1,2
1The University of Tokyo, Department of Mechanical Engineering, Tokyo, Japan.
None:
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.
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