title: Growing a Chemical Garden at the Air-Fluid Interface.
abstract: Here we grow chemical gardens using a novel, quasi two-dimensional, experimental configuration. Buoyant calcium chloride solution is pumped onto the surface of sodium silicate solution. The solutions react to form a precipitation structure on the surface. Initially, an open channel forms that grows in a spiral. This transitions to radially spreading and branching fingers, which typically oscillate in transparency as they grow. The depth of the radial spreading, and the fractal dimension of the finger growth, are surprisingly robust, being insensitive to the pumping rate. The curvature of the channel membrane and the depth of the radially spreading solution can be explained in terms of the solution densities and the interfacial tension across the semipermeable membrane. These unusually beautiful structures provide new insights into the dynamics of precipitation structures and may lead to new technologies where structures are grown instead of assembled.
authors.affiliation: Department of Chemistry, University of Alaska Anchorage , Anchorage, Alaska 99508, United States.|Department of Physics, University of Auckland , Auckland 1010, New Zealand.
authors.forename: Salome
authors.initials: S
authors.lastname: Hussein
authors.affiliation: Department of Chemistry, University of Alaska Anchorage , Anchorage, Alaska 99508, United States.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Maselko
authors.affiliation: Department of Physics, University of Alaska Anchorage , Anchorage, Alaska 99508, United States.
authors.forename: James T
authors.initials: JT
authors.lastname: Pantaleone