This paper demonstrates a simple, yet versatile method for fabricating polymer particles covered with a thin nanodiamond layer by mixing polymer particles with nanodiamonds in supercritical carbon dioxide (scCO(2)) without using any surfactants or special solvents. The surface layering of nanodiamonds was probably based on softening of polymer particles by swelling with scCO(2) and adhesive attachment of nanodiamonds on the surface of polymer particles. Our method enables control of the thickness of nanodiamonds-layered shell by scCO(2) conditions such as temperature and pressure and is applicable to other inorganic nanomaterials. (C) 2017 Elsevier B.V. All rights reserved.