The effect of random positioning on the packing of particles adhering to the surface of a central particle

The number of (outer) particles, in a random-packed monolayer, adhering to the surface of a central particle has been evaluated by means of computer simulation. An approximate equation accounting for the influence of the central-to-outer particle size ratio is derived. This equation contains the average distance between two adjacent outer particles as a fitting parameter. It is found that the average distance between the centers of two contiguous outer particles is equal to λ = 4/3 times their diameter. The corresponding number of randomly packed particles equals 1/λ2 (= 0.56) times the maximum possible (hexagonal-packed) number of particles which can adhere to a given central particle.