Two-dimensional crystal growth from undersaturated solutions.
The solubility of a substance is commonly understood as the minimum concentration necessary for the condensation of a solid phase from solution. Here we report the nucleation and growth of ionic compounds from aqueous concentrations on the order of 0.1 times the solubility. The condensation is catalyzed by a foreign substrate, and the new phase grows as a crystalline monolayer. Undersaturated growth is observed only in cases where the dissolved compound is isomorphic with the substrate and the interaction strength between a dissolved-ion/substrate-ion pair exceeds that between the two dissolved ions. These results are consistent with a simple model in which favorable ion-surface interactions lead to ion enrichment and supersaturation in the two-dimensional interfacial zone.
Murdaugh
Anne E
AE
Department of Physics and Department of Materials Science & Engineering, University of Arizona, Tucson, Arizona 85721, USA.
Liddelow
Mary
M
Schmidt
Anneliese M
AM
Manne
Srinivas
S