Figure 2.

We model the directional solidification of a drying colloidal dispersion, in one dimension. The colloidal dispersion enters from a reservoir on the far left, at some volume fraction ϕ=ϕ₀ and evaporation occurs at the far right at a rate . A solid deposit grows in from the drying edge at a velocity w. Near the liquid–solid transition the particles slow down, from an initial velocity to zero, and concentrate until they reach a final volume fraction ϕ_f. This results in a thin transition region, governed by a balance between advection and diffusion, where the properties of the dispersion change rapidly. This drying front grows into the cell, at velocity w, along with the solid deposit.