Figure 4. Breakup of clay ribbon into rotating domains.

Clay concentration is 0.5 wt%. The ribbon is stable at field strength of 200 Vmm⁻¹ (a). At 600 Vmm⁻¹ (b), the ribbon breaks up into several domains with continuous rotation (vortices) as illustrated in the cartoon (c). The drop remains oblate even at high fields, similar to a pure silicone drop in castor oil that experience EHD flow deformation (see also Supplementary Movie 1). The drop radius is about 1 mm. The E-field direction is horizontal in the plane of the panels, as indicated by the arrows.