Ocean-ridge-like growth in silica tubes
Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, Université Paris Diderot - Paris, France, EU
Corresponding author: email@example.com
Accepted: 12 February 2010
Complex shapes can occur through successions of instabilities, like in the growth of chemical gardens, where a semi-permeable membrane precipitates at the interface between a sodium silicate solution and a metal salt. Instead of letting the osmotic pressure during the metal salt dissolution lead the dynamics of the growth, we inject a ferric sulfate solution into a sodium silicate solution, both of controlled concentration, controlling also the other hydrodynamical parameters. Although qualitatively distinct regimes can be obtained, we focus here on a previously unobserved regime where the reactive interface grows in tubular fingering patterns with ocean-ridge-like dynamics: the tubes grow evenly on both sides of a central fracture where the silica deposits continuously. Our experiments show that the whole dynamics is intrinsically related to the precipitation occurring at the interface: the tubes elongation rate remains constant even when the injection rate is varying, but strongly depends on the limiting concentration in injected solution, thus on the reaction rate.
PACS: 47.20.Hw – Morphological instability; phase changes / 47.54.-r – Pattern selection; pattern formation
© EPLA, 2010