Theory of coagulation of metal nanodust clouds into micro-solids

We describe briefly a possible coagulation mechanism for unipolar nanodust clouds of 3 nm single charged metal nanoparticles. A theoretical dependence of the critical cloud concentration vs the Hamaker constant is derived and compared with available experimental data for Au, Ag, and Cu. Curious empty 1-3 um spheres, precipitated from the clouds in the result of coagulation, are discussed. The work may be interesting for nanoprinting and initial planetary formation mechanisms as establishing a bridge between nano and micro solids.