Fig. 1: Schematic illustration of EC under a viscosity gradient.
From: Electroconvective viscous fingering in a single polyelectrolyte fluid on a charge selective surface
Schematic illustration and experimental images of a, b circular EC in ordinary electrolytes without viscosity gradient, c–e electroconvective viscous fingering in an anodic polyelectrolyte (PAA) solution with a viscosity gradient in the \(+y\) direction (straight (d) and ramified (e)), and f, g suppressed EC in a cathodic polyelectrolyte (PQ-10) solution with a viscosity gradient in \(-y\) direction. The depletion zone is exaggerated in scale for intuitive understanding in schematics. Inset graphs in (a, c, f) are ion concentrations (\({c}_{o}\), black lines), polyelectrolyte concentration (\({c}_{p}\)) and fluid viscosity (\({\mu }_{a,b}\), red lines) profiles in electrolytes. In all three cases, the ion concentrations show the same profile, which has the depletion zone near the membrane. Experimental images were taken by adding fluorescent dyes (b, g) or a liquid pH indicator (d, e) (see “Methods”).
