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Active structuring of colloidal armour on liquid drops.

Dommersnes P, Rozynek Z, Mikkelsen A, Castberg R, Kjerstad K, Hersvik K, Otto Fossum J - Nat Commun (2013)

Bottom Line: Here we report that electrohydrodynamic and electro-rheological effects in leaky-dielectric liquid drops can be used to structure and dynamically control colloidal particle assemblies at drop surfaces, including electric-field-assisted convective assembly of jammed colloidal 'ribbons', electro-rheological colloidal chains confined to a two-dimensional surface and spinning colloidal domains on that surface.In addition, we demonstrate the size control of 'pupil'-like openings in colloidal shells.We anticipate that electric field manipulation of colloids in leaky dielectrics can lead to new routes of colloidosome assembly and design for 'smart armoured' droplets.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Norwegian University of Science and Technology, Hoegskoleringen 5, N-7491 Trondheim, Norway.

ABSTRACT
Adsorption and assembly of colloidal particles at the surface of liquid droplets are at the base of particle-stabilized emulsions and templating. Here we report that electrohydrodynamic and electro-rheological effects in leaky-dielectric liquid drops can be used to structure and dynamically control colloidal particle assemblies at drop surfaces, including electric-field-assisted convective assembly of jammed colloidal 'ribbons', electro-rheological colloidal chains confined to a two-dimensional surface and spinning colloidal domains on that surface. In addition, we demonstrate the size control of 'pupil'-like openings in colloidal shells. We anticipate that electric field manipulation of colloids in leaky dielectrics can lead to new routes of colloidosome assembly and design for 'smart armoured' droplets.

No MeSH data available.


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.
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f4: 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.

Mentions: At lower clay concentration (0.5 wt%), increasing the field strength induces an instability of the ribbon, it breaks up into several counter-rotating colloidal assemblies (shown in Fig. 4 and Supplementary Movie 1). Particles that are less conducting than their surrounding liquid can spin in DC electric fields, known as Quincke rotation37. In the present case, clay is more conducting than the surrounding liquid, and we therefore exclude Quincke rotation as the mechanism here. However, our observations are in line with previous work showing that conducting particles in bulk can assemble and form counter-rotating vortices38.


Active structuring of colloidal armour on liquid drops.

Dommersnes P, Rozynek Z, Mikkelsen A, Castberg R, Kjerstad K, Hersvik K, Otto Fossum J - Nat Commun (2013)

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.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4355650&req=5

f4: 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.
Mentions: At lower clay concentration (0.5 wt%), increasing the field strength induces an instability of the ribbon, it breaks up into several counter-rotating colloidal assemblies (shown in Fig. 4 and Supplementary Movie 1). Particles that are less conducting than their surrounding liquid can spin in DC electric fields, known as Quincke rotation37. In the present case, clay is more conducting than the surrounding liquid, and we therefore exclude Quincke rotation as the mechanism here. However, our observations are in line with previous work showing that conducting particles in bulk can assemble and form counter-rotating vortices38.

Bottom Line: Here we report that electrohydrodynamic and electro-rheological effects in leaky-dielectric liquid drops can be used to structure and dynamically control colloidal particle assemblies at drop surfaces, including electric-field-assisted convective assembly of jammed colloidal 'ribbons', electro-rheological colloidal chains confined to a two-dimensional surface and spinning colloidal domains on that surface.In addition, we demonstrate the size control of 'pupil'-like openings in colloidal shells.We anticipate that electric field manipulation of colloids in leaky dielectrics can lead to new routes of colloidosome assembly and design for 'smart armoured' droplets.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Norwegian University of Science and Technology, Hoegskoleringen 5, N-7491 Trondheim, Norway.

ABSTRACT
Adsorption and assembly of colloidal particles at the surface of liquid droplets are at the base of particle-stabilized emulsions and templating. Here we report that electrohydrodynamic and electro-rheological effects in leaky-dielectric liquid drops can be used to structure and dynamically control colloidal particle assemblies at drop surfaces, including electric-field-assisted convective assembly of jammed colloidal 'ribbons', electro-rheological colloidal chains confined to a two-dimensional surface and spinning colloidal domains on that surface. In addition, we demonstrate the size control of 'pupil'-like openings in colloidal shells. We anticipate that electric field manipulation of colloids in leaky dielectrics can lead to new routes of colloidosome assembly and design for 'smart armoured' droplets.

No MeSH data available.