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.

A Self‐Assembled Planar Chemical Garden in a 3D Solution

“…Finally, we determined the fractal dimension of the developed structures using the well‐known box counting method and for the waterlilies was approximately 1.83, while for the branches part of the tree structure was 1.79. This is in a close accordance to a previous structure generated in the air‐fluid interface that was reported 1.7 . In conclusion, we demonstrate here that quasi‐2D chemical gardens can form spontaneously when two solutions in a 3D system come in contact without the need of a confined geometry or pumping one reactant in the other.…”

“…This is in a close accordance to a previous structure generated in the airfluid interface that was reported 1.7. [15] In conclusion, we demonstrate here that quasi-2D chemical gardens can form spontaneously when two solutions in a 3D system come in contact without the need of a confined geometry or pumping one reactant in the other. To our knowledge this is the first time that a planar chemical garden is produced by selfassembly in a 3D solution.…”

“…Finally, the generation of a quasi‐2D chemical garden was described when the precipitant grew at the air‐solution interface. In this case, the delivery of the solution containing calcium ions was performed with a pump at the bottom of a dish containing the silicate solution . Here we present a simple system consisting of calcium chloride and sodium phosphate that upon the addition of EDTA spontaneously generates a quasi‐2D chemical garden on the surface of the sodium phosphate solution.…”

“…In this case, the delivery of the solution containing calcium ions was performed with a pump at the bottom of a dish containing the silicate solution. [15] Here we present a simple system consisting of calcium chloride and sodium phosphate that upon the addition of EDTA spontaneously generates a quasi-2D chemical garden on the surface of the sodium phosphate solution.The experiments were conducted by placing a drop of 0.080 ml calcium chloride at various concentrations in a glass beaker containing 25 ml sodium phosphate solution of various concentrations adjusted (with NaOH) to pH 11.5 (Figure 1). Upon contact of the two solutions, a thin semipermeable membrane is formed that separates the reactants and creates a closed chemobrionic system (bubble).…”

Diffúzió- és áramlásvezérelt csapadékmintázatok vizsgálata

“…Réz-foszfát csapadékok képe [80]. látható összetett mintázat képződését találtak a kalcium-szilikát rendszerben [81]. A kísérlet során egy nyitott edény alján lévő furaton keresztül áramoltatták a kalciumionok oldatát a nátrium-szilikát-oldat felszínére egy perisztaltikus pumpa segítségével.…”