Pattern formation by two precipitated species during solvent evaporation.

We investigate the pattern formation produced by precipitated species during solvent evaporation through the numerical solution of a set of partial differential equations that account for the mechanisms of evaporation, diffusion, and precipitation. A pattern is formed because solvent evaporation provokes precipitation of species near the border of the system producing ringlike depositions from the edge to the center. Solvent evaporation is modeled as occurs with a liquid drop on a surface.