Figure 4.

A proposed mechanism of the combined structure formation. a Ag particles in toluene; b movement of contact line and the development of a sinusoidal interface where particles are captured; c droplet formation; d droplets shrinking (not to scale); e Outward flow and deepening of particles toward the substrate; f spot formation due to the deposition of the particles on the substrate and ring formation due the outward compensation

Al-Harthi et al. Nanoscale Research Letters 2010 5:1737-1743   doi:10.1007/s11671-010-9703-1