The packings of non-adhesive granular matter have been extensively studied, with two well-known packing limits identified as the Random Close Packing (RCP) and the Random Loose Packing (RLP). However, for micron-sized particles, the presence of adhesive interactions such as van der Waals forces could intrinsically change the packing properties, which have not been well understood. In this work, we systematically generate a large set of micro-particle packings with arbitrary adhesion and friction by means of adhesive DEM simulation. A dimensionless adhesion parameter and the friction coefficient  are found to well characterize the bulk properties of the adhesive packings. A universal equation of state  as well as a new phase diagram is derived to describe the ensemble of the generated packings, which immensely expands the classical phase diagram of the jammed granular matter (Song C, Wang P, Makse HA, Nature, 2008, 453(7195): 629-632).

Publications:

Liu WW, Li SQ*, Baule A, Makse HA*.  Adhesive loose packings of small dry particles. Soft Matter,  11(32), 6492-6498 (2015).

Liu WW, Jin Y, Chen S, Makse HA, Li SQ*. Equation of state for random sphere packings with arbitrary adhesion and friction. Soft Matter, 13, 421-427 (2017).