title: Drying of complex suspensions.
abstract: We investigate the 3D structure and drying dynamics of complex mixtures of emulsion droplets and colloidal particles, using confocal microscopy. Air invades and rapidly collapses large emulsion droplets, forcing their contents into the surrounding porous particle pack at a rate proportional to the square of the droplet radius. By contrast, small droplets do not collapse, but remain intact and are merely deformed. A simple model coupling the Laplace pressure to Darcy's law correctly estimates both the threshold radius separating these two behaviors, and the rate of large-droplet evacuation. Finally, we use these systems to make novel hierarchical structures.
authors.affiliation: Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Alexis
authors.initials: A
authors.lastname: Bergès
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Lu
authors.forename: André R
authors.initials: AR
authors.lastname: Studart
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Schofield
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Oki
authors.forename: Simon
authors.initials: S
authors.lastname: Davies
authors.forename: David A
authors.initials: DA
authors.lastname: Weitz