Viscous Fingering Induced by a pH-Sensitive Clock Reaction

A pH-changing clock chemical system, also known to induce changes in viscosity, is shown experimentally to induce a viscous fingering instability during the displacement of reactive solutions in a Hele-Shaw cell. Specifically, a low-viscosity solution of formaldehyde is displaced by a more viscous s...

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Bibliographic Details
Published in:Langmuir 2019-03, Vol.35 (11), p.4182-4188
Main Authors: Escala, D. M, De Wit, A, Carballido-Landeira, J, Muñuzuri, A. P
Format: Article
Language:English
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Summary:A pH-changing clock chemical system, also known to induce changes in viscosity, is shown experimentally to induce a viscous fingering instability during the displacement of reactive solutions in a Hele-Shaw cell. Specifically, a low-viscosity solution of formaldehyde is displaced by a more viscous solution of sulfite and of a pH-sensitive poly­(acrylic acid) polymer. The pH change triggered by the formaldehyde–sulfite clock reaction in the reactive contact zone between the two solutions affects the polymer and induces a local increase of the viscosity that destabilizes the displacement via a viscous fingering instability. The influence of changes in the chemical parameters on this fingering instability is analyzed using different techniques and the results are compared with numerical simulations.
ISSN:0743-7463
1520-5827
DOI:10.1021/acs.langmuir.8b03834