title: Dips and rims in dried colloidal films.
abstract: We describe a spatial pattern arising from the nonuniform evaporation of a colloidal film. Immediately after the film deposition, an obstacle is positioned above its free surface, minimizing evaporation at this location. In a first stage, the film dries everywhere but under the obstacle, where a liquid region remains. Subsequently, this liquid region evaporates near its boundaries with the dry film. This loss of water causes a flow of liquid and particles from the center of the obstructed region to its periphery. The final film has a dip surrounded by a rim whose diameter is set by the obstacle. This turns out to be a simple technique for structuring films of nanometric thickness.
authors.affiliation: PMMH-ESPCI-P6-P7, CNRS UMR 7636, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Parneix
authors.forename: P
authors.initials: P
authors.lastname: Vandoolaeghe
authors.forename: V S
authors.initials: VS
authors.lastname: Nikolayev
authors.forename: D
authors.initials: D
authors.lastname: Quéré
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: B
authors.initials: B
authors.lastname: Cabane