Micrometer-sized particles in a two-dimensional self-assembly during drying of liquid film.

We computed the self-organization process of a monodisperse collection of spherical micrometer-sized particles trapped in a two-dimensional thin liquid film isothermally dried on a chemically inert substrate. The substrate is either flat or indented to create linear stripes on its surface. The numerical results are illustrated and discussed in the light of experimental ones obtained from the drying of a water-based suspension of diamond particles (d{50}=10 microm) on a glass substrate. The drying of the suspension on a flat substrate leads to the formation of linear patterns and small clusters of micrometer-sized particles distributed over the whole surface of the substrate, whereas the drying of the suspension on an indented substrate leads to the aggregation of the particles along one side of the stripe which has a higher roughness than the other side of the stripe. This is an easy experimental way to obtain colloidal self-organized patterns.